Astronomical Data
The U.S. Naval Observatory (USNO) computes astronomical data. Therefore, the NWS does not record, certify, or authenticate astronomical data. Computed times of sunrise, sunset, moonrise, moonset; and twilight, moon phases and other astronomical data are available from USNO's Astronomical Applications Department (http://www.usno.navy.mil/USNO/astronomical-applications/data-services).
Seasons
| Year |
Daylight
Saving Time
Begins at 2 am |
Spring
Begins
(MDT) |
Summer
Begins
(MDT) |
Autumn
Begins
(MDT) |
Daylight
Saving Time
Ends at 2 am |
Winter
Begins
(MST) |
| 2011 |
Mar 13 |
Mar 20
5:21 pm |
Jun 21
11:16 am |
Sep 23
3:04 am |
Nov 6 |
Dec 21
10:30 pm |
| 2012 |
Mar 11 |
Mar 19
11:14 pm |
Jun 20
5:09 pm |
Sep 22
8:49 am |
Nov 4 |
Dec 21
4:11 am |
| 2013 |
Mar 10 |
Mar 20
5:02 am |
Jun 20
11:04 pm |
Sep 22
2:44 pm |
Nov 3 |
Dec 21
10:11 am |
For more information regarding astronomical data, contact:
U.S. Naval Observatory
ATTN: Code AA
3450 Massachusetts Ave. NW
Washington, DC 20392-5420
828-271-4800
FAX: 828-271-4876
|
www.weather.gov 
