To find your place from Greenwich Mean Time, see below.
I live in Portland so mine is normally -8 and is -7 during daylight savings time.


                Standard  Daylight Savings
                  Time         Time
    Atlantic
    Eastern        EST          EDT
    Central        CST          CDT
    Mountain       MST          MDT
    Pacific        PST          PDT
    Alaska
    Hawaii

Standard time: 

    GMT     ATL  EST  CST  MST  PST  ALA  HAW
difference   -4   -5   -6   -7   -8   -9  -10
    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)

Summertime (Daylight savings time) for those states that 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)