Universal Time |
Weather forecasts and observations are always made with respect to time.
By convention, meteorologists use just one time zone: Universal Time, Coordinated (UTC).
They also use the twenty four hour clock (where 0000 = midnight UTC).
The date/time stamp on each forecast image represents the time at which the forecast is valid, measured in UTC. This date/time stamp has the following format: yy mm dd / hh 00V fff
For example, a forecast with the following date/time stamp:
19991101/0000V048 is a 48-hour forecast valid 0000 UTC November 1, 1999. This is equivalent to 7:00 PM Eastern Standard Time on October 31. If you do not understand why, keep reading....
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Time Zones |
To convert to local time, we
must know the difference between the local time zone and UTC.
The time zones and conversions for North America and the Pacific are:
Zone | Standard Time | Daylight Savings Time -------- | --------------------------- | ---------------------------- | Abbreviation Conversion | Abbreviation Conversion Atlantic | UTC - 4 hrs | UTC - 3 hrs Eastern | EST UTC - 5 hrs | EDT UTC - 4 hrs Central | CST UTC - 6 hrs | CDT UTC - 5 hrs Mountain | MST UTC - 7 hrs | MDT UTC - 6 hrs Pacific | PST UTC - 8 hrs | PDT UTC - 7 hrs Alaska | UTC - 9 hrs | UTC - 8 hrs Hawaii | UTC - 10 hrs | UTC - 9 hrs |
Standard Time Conversion Table |
UTC ATL EST CST MST PST ALA HAW 00 8P* 7P* 6P* 5P* 4P* 3P* 2P* 01 9P* 8P* 7P* 6P* 5P* 4P* 3P* 02 10P* 9P* 8P* 7P* 6P* 5P* 4P* 03 11P* 10P* 9P* 8P* 7P* 6P* 5P* 04 12A 11P* 10P* 9P* 8P* 7P* 6P* 05 1A 12A 11P* 10P* 9P* 8P* 7P* 06 2A 1A 12A 11P* 10P* 9P* 8P* 07 3A 2A 1A 12A 11P* 10P* 9P* 08 4A 3A 2A 1A 12A 11P* 10P* 09 5A 4A 3A 2A 1A 12A 11P* 10 6A 5A 4A 3A 2A 1A 12A 11 7A 6A 5A 4A 3A 2A 1A 12 8A 7A 6A 5A 4A 3A 2A 13 9A 8A 7A 6A 5A 4A 3A 14 10A 9A 8A 7A 6A 5A 4A 15 11A 10A 9A 8A 7A 6A 5A 16 12P 11A 10A 9A 8A 7A 6A 17 1P 12P 11A 10A 9A 8A 7A 18 2P 1P 12P 11A 10A 9A 8A 19 3P 2P 1P 12P 11A 10A 9A 20 4P 3P 2P 1P 12P 11A 10A 21 5P 4P 3P 2P 1P 12P 11A 22 6P 5P 4P 3P 2P 1P 12P 23 7P 6P 5P 4P 3P 2P 1P * represents previous day (i.e. 03 hours 23 January 93 is 8PM-MST 22 January) |
Daylight Savings Time Conversion Table |
Note: Not all states observe Daylight Savings Time.
For those that do not, use the standard time table all year.
GMT EDT CDT MDT PDT difference -4 -5 -6 -7 00 8P* 7P* 6P* 5P* 01 9P* 8P* 7P* 6P* 02 10P* 9P* 8P* 7P* 03 11P* 10P* 9P* 8P* 04 12A 11P* 10P* 9P* 05 1A 12A 11P* 10P* 06 2A 1A 12A 11P* 07 3A 2A 1A 12A 08 4A 3A 2A 1A 09 5A 4A 3A 2A 10 6A 5A 4A 3A 11 7A 6A 5A 4A 12 8A 7A 6A 5A 13 9A 8A 7A 6A 14 10A 9A 8A 7A 15 11A 10A 9A 8A 16 12P 11A 10A 9A 17 1P 12P 11A 10A 18 2P 1P 12P 11A 19 3P 2P 1P 12P 20 4P 3P 2P 1P 21 5P 4P 3P 2P 22 6P 5P 4P 3P 23 7P 6P 5P 4P * represents previous day (i.e. 03 hours 23 June is 9PM-MDT 22 June) |