How AZMET denotes Days and Hours


AZMET raw data files use the Day-of-Year (DOY) numbering system. This is a common format used in research data and by the military. The Day-of-Year system ignores the existance of months and numbers each day of the year consecutively.
During normal years we number each day of the year from 1 to 365 During leap years we insert the 'leap day' (Feb 29), at Day-of-Year 60, thus shifting the rest of the year 'down' by one day. The Day-of-Year system is used in both the Daily and Hourly data files.

Note:
There are some other weather data collection agencies which use different calendar formats for their data. They set the length of all years to a 366 days. Their 'leap day' (Feb 29; DOY 60) is left blank (zeros or null data values) for non-leap years. During leap years the leap day position does contain data. AZMET does not use this method. Our years vary in length.


AZMET uses a 24 hour clock.
We number each hour of the day from 1 to 24.
Obviously, this is used in the Hourly data files.
[We do not use the 'digital clock' with colon format (ie 1:00 to 24:00).
Nor do we use the 100 to 2400 format.]

All AZMET data are collected, stored and presented in
local 'Arizona' time, which is in the 'Mountain Standard' time zone.
Arizona does not participate in Daylight Savings Time.
Therefore, the times listed in the AZMET data files are
always seven hours 'behind' Coordinated Universal Time (UTC)
(aka: Greenwich Mean time; Zulu time).




Below are several tables and lists, to aid you in visualizing the Day-of-Year system : In this first table, the Day-of-Year numbers are grouped by month : Day-of-Year by Month ======================================= Normal Year Leap Year -------------- --------------- Jan 1 - 31 Jan 1 - 31 Feb 32 - 59 Feb 32 - 60 Mar 60 - 90 Mar 61 - 91 Apr 91 - 120 Apr 92 - 121 May 121 - 151 May 122 - 152 Jun 152 - 181 Jun 153 - 182 Jul 182 - 212 Jul 183 - 213 Aug 213 - 243 Aug 214 - 244 Sep 244 - 273 Sep 245 - 274 Oct 274 - 304 Oct 275 - 305 Nov 305 - 334 Nov 306 - 335 Dec 335 - 365 Dec 336 - 366

In this second calendar table, The upper number in each box represents the normal calendar day of the month. The lower number in each box represents the Day-of-Year (DOY).
 January
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|                           |
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|                           |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 February
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 | 32| 33| 34| 35| 36| 37| 38| 39| 40| 41| 42| 43| 44| 45| 46| 47| 48| 49| 50|
 +---+---+---+---+---+---+---+---+---+******-+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28 * 29 * NOTE: During leap years, add 1  |
 | 51| 52| 53| 54| 55| 56| 57| 58| 59 * 60 * to each Day-of-Year after FEB 29|
 +---+---+---+---+---+---+---+---+---+******-+---+---+---+---+---+---+---+---+
                                       
 March
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 | 60| 61| 62| 63| 64| 65| 66| 67| 68| 69| 70| 71| 72| 73| 74| 75| 76| 77| 78|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|    Add 1 to DOY           |
 | 79| 80| 81| 82| 83| 84| 85| 86| 87| 88| 89| 90|      during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 April
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 | 91| 92| 93| 94| 95| 96| 97| 98| 99|100|101|102|103|104|105|106|107|108|109|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30|        Add 1 to DOY           |
 |110|111|112|113|114|115|116|117|118|119|120|          during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+-------------------------------+

 May
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |121|122|123|124|125|126|127|128|129|130|131|132|133|134|135|136|137|138|139|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|    Add 1 to DOY           |
 |140|141|142|143|144|145|146|147|148|149|150|151|      during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 June
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |152|153|154|155|156|157|158|159|160|161|162|163|164|165|166|167|168|169|170|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30|        Add 1 to DOY           |
 |171|172|173|174|175|176|177|178|179|180|181|          during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 July
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |182|183|184|185|186|187|188|189|190|191|192|193|194|195|196|197|198|199|200|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|    Add 1 to DOY           |
 |201|202|203|204|205|206|207|208|209|210|211|212|      during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 August
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |213|214|215|216|217|218|219|220|221|222|223|224|225|226|227|228|229|230|231|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|    Add 1 to DOY           |
 |232|233|234|235|236|237|238|239|240|241|242|243|      during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---------------------------+

 September
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |244|245|246|247|248|249|250|251|252|253|254|255|256|257|258|259|260|261|262|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30|        Add 1 to DOY           |
 |263|264|265|266|267|268|269|270|271|272|273|          during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 October
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |274|275|276|277|278|279|280|281|282|283|284|285|286|287|288|289|290|291|292|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|    Add 1 to DOY           |
 |293|294|295|296|297|298|299|300|301|302|303|304|      during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 November
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |305|306|307|308|309|310|311|312|313|314|315|316|317|318|319|320|321|322|323|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30|        Add 1 to DOY           |
 |324|325|326|327|328|329|330|331|332|333|334|          during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

 December
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 |  1|  2|  3|  4|  5|  6|  7|  8|  9| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19|
 |335|336|337|338|339|340|341|342|343|344|345|346|347|348|349|350|351|352|353|
 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 | 20| 21| 22| 23| 24| 25| 26| 27| 28| 29| 30| 31|    Add 1 to DOY           |
 |354|355|356|357|358|359|360|361|362|363|364|365|      during leap years.   |
 +---+---+---+---+---+---+---+---+---+---+---+---+---------------------------+


Julian     Normal     Leap
 Day        Year      Year
-----      ------    ------
  1    =   Jan  1    Jan  1
  2    =   Jan  2    Jan  2
  3    =   Jan  3    Jan  3
  4    =   Jan  4    Jan  4
  5    =   Jan  5    Jan  5
  6    =   Jan  6    Jan  6
  7    =   Jan  7    Jan  7
  8    =   Jan  8    Jan  8
  9    =   Jan  9    Jan  9
 10    =   Jan 10    Jan 10
 11    =   Jan 11    Jan 11
 12    =   Jan 12    Jan 12
 13    =   Jan 13    Jan 13
 14    =   Jan 14    Jan 14
 15    =   Jan 15    Jan 15
 16    =   Jan 16    Jan 16
 17    =   Jan 17    Jan 17
 18    =   Jan 18    Jan 18
 19    =   Jan 19    Jan 19
 20    =   Jan 20    Jan 20
 21    =   Jan 21    Jan 21
 22    =   Jan 22    Jan 22
 23    =   Jan 23    Jan 23
 24    =   Jan 24    Jan 24
 25    =   Jan 25    Jan 25
 26    =   Jan 26    Jan 26
 27    =   Jan 27    Jan 27
 28    =   Jan 28    Jan 28
 29    =   Jan 29    Jan 29
 30    =   Jan 30    Jan 30
 31    =   Jan 31    Jan 31
 32    =   Feb  1    Feb  1
 33    =   Feb  2    Feb  2
 34    =   Feb  3    Feb  3
 35    =   Feb  4    Feb  4
 36    =   Feb  5    Feb  5
 37    =   Feb  6    Feb  6
 38    =   Feb  7    Feb  7
 39    =   Feb  8    Feb  8
 40    =   Feb  9    Feb  9
 41    =   Feb 10    Feb 10
 42    =   Feb 11    Feb 11
 43    =   Feb 12    Feb 12
 44    =   Feb 13    Feb 13
 45    =   Feb 14    Feb 14
 46    =   Feb 15    Feb 15
 47    =   Feb 16    Feb 16
 48    =   Feb 17    Feb 17
 49    =   Feb 18    Feb 18
 50    =   Feb 19    Feb 19
 51    =   Feb 20    Feb 20
 52    =   Feb 21    Feb 21
 53    =   Feb 22    Feb 22
 54    =   Feb 23    Feb 23
 55    =   Feb 24    Feb 24
 56    =   Feb 25    Feb 25
 57    =   Feb 26    Feb 26
 58    =   Feb 27    Feb 27
 59    =   Feb 28    Feb 28
 60    =   Mar  1    Feb 29
 61    =   Mar  2    Mar  1
 62    =   Mar  3    Mar  2
 63    =   Mar  4    Mar  3
 64    =   Mar  5    Mar  4
 65    =   Mar  6    Mar  5
 66    =   Mar  7    Mar  6
 67    =   Mar  8    Mar  7
 68    =   Mar  9    Mar  8
 69    =   Mar 10    Mar  9
 70    =   Mar 11    Mar 10
 71    =   Mar 12    Mar 11
 72    =   Mar 13    Mar 12
 73    =   Mar 14    Mar 13
 74    =   Mar 15    Mar 14
 75    =   Mar 16    Mar 15
 76    =   Mar 17    Mar 16
 77    =   Mar 18    Mar 17
 78    =   Mar 19    Mar 18
 79    =   Mar 20    Mar 19
 80    =   Mar 21    Mar 20
 81    =   Mar 22    Mar 21
 82    =   Mar 23    Mar 22
 83    =   Mar 24    Mar 23
 84    =   Mar 25    Mar 24
 85    =   Mar 26    Mar 25
 86    =   Mar 27    Mar 26
 87    =   Mar 28    Mar 27
 88    =   Mar 29    Mar 28
 89    =   Mar 30    Mar 29
 90    =   Mar 31    Mar 30
 91    =   Apr  1    Mar 31
 92    =   Apr  2    Apr  1
 93    =   Apr  3    Apr  2
 94    =   Apr  4    Apr  3
 95    =   Apr  5    Apr  4
 96    =   Apr  6    Apr  5
 97    =   Apr  7    Apr  6
 98    =   Apr  8    Apr  7
 99    =   Apr  9    Apr  8
100    =   Apr 10    Apr  9
101    =   Apr 11    Apr 10
102    =   Apr 12    Apr 11
103    =   Apr 13    Apr 12
104    =   Apr 14    Apr 13
105    =   Apr 15    Apr 14
106    =   Apr 16    Apr 15
107    =   Apr 17    Apr 16
108    =   Apr 18    Apr 17
109    =   Apr 19    Apr 18
110    =   Apr 20    Apr 19
111    =   Apr 21    Apr 20
112    =   Apr 22    Apr 21
113    =   Apr 23    Apr 22
114    =   Apr 24    Apr 23
115    =   Apr 25    Apr 24
116    =   Apr 26    Apr 25
117    =   Apr 27    Apr 26
118    =   Apr 28    Apr 27
119    =   Apr 29    Apr 28
120    =   Apr 30    Apr 29
121    =   May  1    Apr 30
122    =   May  2    May  1
123    =   May  3    May  2
124    =   May  4    May  3
125    =   May  5    May  4
126    =   May  6    May  5
127    =   May  7    May  6
128    =   May  8    May  7
129    =   May  9    May  8
130    =   May 10    May  9
131    =   May 11    May 10
132    =   May 12    May 11
133    =   May 13    May 12
134    =   May 14    May 13
135    =   May 15    May 14
136    =   May 16    May 15
137    =   May 17    May 16
138    =   May 18    May 17
139    =   May 19    May 18
140    =   May 20    May 19
141    =   May 21    May 20
142    =   May 22    May 21
143    =   May 23    May 22
144    =   May 24    May 23
145    =   May 25    May 24
146    =   May 26    May 25
147    =   May 27    May 26
148    =   May 28    May 27
149    =   May 29    May 28
150    =   May 30    May 29
151    =   May 31    May 30
152    =   Jun  1    May 31
153    =   Jun  2    Jun  1
154    =   Jun  3    Jun  2
155    =   Jun  4    Jun  3
156    =   Jun  5    Jun  4
157    =   Jun  6    Jun  5
158    =   Jun  7    Jun  6
159    =   Jun  8    Jun  7
160    =   Jun  9    Jun  8
161    =   Jun 10    Jun  9
162    =   Jun 11    Jun 10
163    =   Jun 12    Jun 11
164    =   Jun 13    Jun 12
165    =   Jun 14    Jun 13
166    =   Jun 15    Jun 14
167    =   Jun 16    Jun 15
168    =   Jun 17    Jun 16
169    =   Jun 18    Jun 17
170    =   Jun 19    Jun 18
171    =   Jun 20    Jun 19
172    =   Jun 21    Jun 20
173    =   Jun 22    Jun 21
174    =   Jun 23    Jun 22
175    =   Jun 24    Jun 23
176    =   Jun 25    Jun 24
177    =   Jun 26    Jun 25
178    =   Jun 27    Jun 26
179    =   Jun 28    Jun 27
180    =   Jun 29    Jun 28
181    =   Jun 30    Jun 29
182    =   Jul  1    Jun 30
183    =   Jul  2    Jul  1
184    =   Jul  3    Jul  2
185    =   Jul  4    Jul  3
186    =   Jul  5    Jul  4
187    =   Jul  6    Jul  5
188    =   Jul  7    Jul  6
189    =   Jul  8    Jul  7
190    =   Jul  9    Jul  8
191    =   Jul 10    Jul  9
192    =   Jul 11    Jul 10
193    =   Jul 12    Jul 11
194    =   Jul 13    Jul 12
195    =   Jul 14    Jul 13
196    =   Jul 15    Jul 14
197    =   Jul 16    Jul 15
198    =   Jul 17    Jul 16
199    =   Jul 18    Jul 17
200    =   Jul 19    Jul 18
201    =   Jul 20    Jul 19
202    =   Jul 21    Jul 20
203    =   Jul 22    Jul 21
204    =   Jul 23    Jul 22
205    =   Jul 24    Jul 23
206    =   Jul 25    Jul 24
207    =   Jul 26    Jul 25
208    =   Jul 27    Jul 26
209    =   Jul 28    Jul 27
210    =   Jul 29    Jul 28
211    =   Jul 30    Jul 29
212    =   Jul 31    Jul 30
213    =   Aug  1    Jul 31
214    =   Aug  2    Aug  1
215    =   Aug  3    Aug  2
216    =   Aug  4    Aug  3
217    =   Aug  5    Aug  4
218    =   Aug  6    Aug  5
219    =   Aug  7    Aug  6
220    =   Aug  8    Aug  7
221    =   Aug  9    Aug  8
222    =   Aug 10    Aug  9
223    =   Aug 11    Aug 10
224    =   Aug 12    Aug 11
225    =   Aug 13    Aug 12
226    =   Aug 14    Aug 13
227    =   Aug 15    Aug 14
228    =   Aug 16    Aug 15
229    =   Aug 17    Aug 16
230    =   Aug 18    Aug 17
231    =   Aug 19    Aug 18
232    =   Aug 20    Aug 19
233    =   Aug 21    Aug 20
234    =   Aug 22    Aug 21
235    =   Aug 23    Aug 22
236    =   Aug 24    Aug 23
237    =   Aug 25    Aug 24
238    =   Aug 26    Aug 25
239    =   Aug 27    Aug 26
240    =   Aug 28    Aug 27
241    =   Aug 29    Aug 28
242    =   Aug 30    Aug 29
243    =   Aug 31    Aug 30
244    =   Sep  1    Aug 31
245    =   Sep  2    Sep  1
246    =   Sep  3    Sep  2
247    =   Sep  4    Sep  3
248    =   Sep  5    Sep  4
249    =   Sep  6    Sep  5
250    =   Sep  7    Sep  6
251    =   Sep  8    Sep  7
252    =   Sep  9    Sep  8
253    =   Sep 10    Sep  9
254    =   Sep 11    Sep 10
255    =   Sep 12    Sep 11
256    =   Sep 13    Sep 12
257    =   Sep 14    Sep 13
258    =   Sep 15    Sep 14
259    =   Sep 16    Sep 15
260    =   Sep 17    Sep 16
261    =   Sep 18    Sep 17
262    =   Sep 19    Sep 18
263    =   Sep 20    Sep 19
264    =   Sep 21    Sep 20
265    =   Sep 22    Sep 21
266    =   Sep 23    Sep 22
267    =   Sep 24    Sep 23
268    =   Sep 25    Sep 24
269    =   Sep 26    Sep 25
270    =   Sep 27    Sep 26
271    =   Sep 28    Sep 27
272    =   Sep 29    Sep 28
273    =   Sep 30    Sep 29
274    =   Oct  1    Sep 30
275    =   Oct  2    Oct  1
276    =   Oct  3    Oct  2
277    =   Oct  4    Oct  3
278    =   Oct  5    Oct  4
279    =   Oct  6    Oct  5
280    =   Oct  7    Oct  6
281    =   Oct  8    Oct  7
282    =   Oct  9    Oct  8
283    =   Oct 10    Oct  9
284    =   Oct 11    Oct 10
285    =   Oct 12    Oct 11
286    =   Oct 13    Oct 12
287    =   Oct 14    Oct 13
288    =   Oct 15    Oct 14
289    =   Oct 16    Oct 15
290    =   Oct 17    Oct 16
291    =   Oct 18    Oct 17
292    =   Oct 19    Oct 18
293    =   Oct 20    Oct 19
294    =   Oct 21    Oct 20
295    =   Oct 22    Oct 21
296    =   Oct 23    Oct 22
297    =   Oct 24    Oct 23
298    =   Oct 25    Oct 24
299    =   Oct 26    Oct 25
300    =   Oct 27    Oct 26
301    =   Oct 28    Oct 27
302    =   Oct 29    Oct 28
303    =   Oct 30    Oct 29
304    =   Oct 31    Oct 30
305    =   Nov  1    Oct 31
306    =   Nov  2    Nov  1
307    =   Nov  3    Nov  2
308    =   Nov  4    Nov  3
309    =   Nov  5    Nov  4
310    =   Nov  6    Nov  5
311    =   Nov  7    Nov  6
312    =   Nov  8    Nov  7
313    =   Nov  9    Nov  8
314    =   Nov 10    Nov  9
315    =   Nov 11    Nov 10
316    =   Nov 12    Nov 11
317    =   Nov 13    Nov 12
318    =   Nov 14    Nov 13
319    =   Nov 15    Nov 14
320    =   Nov 16    Nov 15
321    =   Nov 17    Nov 16
322    =   Nov 18    Nov 17
323    =   Nov 19    Nov 18
324    =   Nov 20    Nov 19
325    =   Nov 21    Nov 20
326    =   Nov 22    Nov 21
327    =   Nov 23    Nov 22
328    =   Nov 24    Nov 23
329    =   Nov 25    Nov 24
330    =   Nov 26    Nov 25
331    =   Nov 27    Nov 26
332    =   Nov 28    Nov 27
333    =   Nov 29    Nov 28
334    =   Nov 30    Nov 29
335    =   Dec  1    Nov 30
336    =   Dec  2    Dec  1
337    =   Dec  3    Dec  2
338    =   Dec  4    Dec  3
339    =   Dec  5    Dec  4
340    =   Dec  6    Dec  5
341    =   Dec  7    Dec  6
342    =   Dec  8    Dec  7
343    =   Dec  9    Dec  8
344    =   Dec 10    Dec  9
345    =   Dec 11    Dec 10
346    =   Dec 12    Dec 11
347    =   Dec 13    Dec 12
348    =   Dec 14    Dec 13
349    =   Dec 15    Dec 14
350    =   Dec 16    Dec 15
351    =   Dec 17    Dec 16
352    =   Dec 18    Dec 17
353    =   Dec 19    Dec 18
354    =   Dec 20    Dec 19
355    =   Dec 21    Dec 20
356    =   Dec 22    Dec 21
357    =   Dec 23    Dec 22
358    =   Dec 24    Dec 23
359    =   Dec 25    Dec 24
360    =   Dec 26    Dec 25
361    =   Dec 27    Dec 26
362    =   Dec 28    Dec 27
363    =   Dec 29    Dec 28
364    =   Dec 30    Dec 29
365    =   Dec 31    Dec 30
366    =             Dec 31





              Julian Days by Month
      =======================================
         Normal Year          Leap Year
        --------------      ---------------
        Jan    1 -  31       Jan    1 -  31           
        Feb   32 -  59       Feb   32 -  60           
        Mar   60 -  90       Mar   61 -  91           
        Apr   91 - 120       Apr   92 - 121           
        May  121 - 151       May  122 - 152            
        Jun  152 - 181       Jun  153 - 182            
        Jul  182 - 212       Jul  183 - 213            
        Aug  213 - 243       Aug  214 - 244             
        Sep  244 - 273       Sep  245 - 274            
        Oct  274 - 304       Oct  275 - 305            
        Nov  305 - 334       Nov  306 - 335            
        Dec  335 - 365       Dec  336 - 366            



     Recent Leap Years:                    Past and future Leap Years 
  ============================         ==================================
          * 1984 - Leap Year             1896     1936     1972     2008
            1985                         1904     1940     1976     2012
            1986                         1908     1944     1980     2016
            1987                         1912     1948     1984     2020
          * 1988 - Leap Year             1916     1952     1988     2024
            1989                         1920     1956     1992     2028
            1990                         1924     1960     1996     2032
            1991                         1928     1964     2000     2036
          * 1992 - Leap Year             1932     1968     2004     2040
            1993                             
            1994                              
            1995                              
          * 1996 - Leap Year                    

    (Rule-of-Thumb :  Leap Years = U.S. Presidential Election Years)


     Official Leap Year Rules :

       If a year is evenly divisible by 4 it is a leap year.
       Examples: 1996 / 4 = 499  therefore it is a leap year
                 1997 / 4 = 499.25  therefore it is not a leap year

       First Exception:
       Of those years which are evenly divisible by 4,
       if the year is also evenly divisible by 100, 
       it is NOT a leap year.
       Example: 1900 / 4 = 475
                1900 / 100 = 19   therefore it is NOT a leap year          
      
       Second Exception:
       Of those years which are evenly divisible by 4 and 100,
       if the year is also evenly divisible by 400, 
       it IS a leap year.
       Example: 2000 / 4 = 500
                2000 / 100 = 20
                2000 / 400 = 5   therefore it IS a leap year 
         
                1900 / 400 = 4.75  therefore it is NOT a leap year
      

  The Julian Calendar was developed by Julius Caesar and Egyptian
  astronomer Sosigenes in the year 46 BC.  They sought to create a 12
  month calendar which was based on a solar year; the time it takes for
  the earth to make one full orbit around the sun, which is 365.2422 days.  
  (Prior to this, the Romans and most other civilizations used a lunar or
  lunar-solar hybrid calendar; only Egypt had a strictly solar calendar.)
  They set a normal year to equal 365 days, then designated every forth
  year (leap year) to have 366 days. This was to correct for the partial
  .2422 day which was missing from the current year and from each of the
  previous three years.  To accomplish this they included the 'evenly
  divisible by 4' rule in their calendar.
  The Julian Calendar was adopted by the Council of Nicaea in 325 AD.
  However, by 1582 AD the number of past leap years had overcorrected
  (.2422 multiplied by 4 years = .9688 day, not 1 day)
  and the Julian Calendar had gained 10 days on earth's actual orbital
  position around the sun. If left unchecked, Easter would eventually  
  occur in summer.  To correct this, Pope Gregory XIII dropped 10 days 
  from 1582 and enacted the first and second exceptions ('evenly divisible
  by 100 and by 400') as described above.  The first exception excludes
  a leap year every 100 years.  By using only the first exception, the 
  calendar would, after several centuries, be slightly undercorrected.
  That is, it would have fallen behind earth's true orbital position.
  Realizing this, the Pope's mathematicians added the second exception 
  which includes a leap year every 400 years (1600, 2000, 2400, etc). 
  These rules do not fully correct the calendar to a perfect 365.2422 days 
  per year; by the year 5000 AD it will have gained 1 day and another
  adjustment will be necessary.

  The 'calendar' section of any good Almanac will verify these
  rules regarding leap years


-----



  TIME:
  All AZMET data are collected, stored and presented in 
  local 'Arizona' time, which is in the 'Mountain Standard' time zone.
  Arizona does not participate in Daylight Savings Time.
  Therefore, the times listed in the AZMET data files are 
  always seven hours 'behind' Coordinated Universal Time (UTC)
  (aka: Greenwich Mean time; Zulu time).

        UTC     Arizona    Arizona 12hr
       ------   -------   -------------
        8:00     1:00       1:00 am
        9:00     2:00       2:00 am
       10:00     3:00       3:00 am
       11:00     4:00       4:00 am
       12:00     5:00       5:00 am
       13:00     6:00       6:00 am
       14:00     7:00       7:00 am
       15:00     8:00       8:00 am
       16:00     9:00       9:00 am
       17:00    10:00      10:00 am
       18:00    11:00      11:00 am
       19:00    12:00      12:00 am
       20:00    13:00       1:00 pm
       21:00    14:00       2:00 pm
       22:00    15:00       3:00 pm
       23:00    16:00       4:00 pm
       24:00    17:00       5:00 pm
        1:00    18:00       6:00 pm
        2:00    19:00       7:00 pm
        3:00    20:00       8:00 pm
        4:00    21:00       9:00 pm
        5:00    22:00      10:00 pm
        6:00    23:00      11:00 pm
        7:00    24:00      12:00 pm