off_gmt is the number of hours difference from GMT (aka UTC). These are the number of hours to be added to GMT/UTC to obtain local time for each grid cell. Sample offsets are listed in the table below. since UTC does not use any daylight savings adjustment, the gmt offset will decrease by one hour for those areas using daylight savings. For example, Eastern Standard Time (EST) changes from GMT-5 hours to Eastern Daylight Time (EDT) at GMT-4 hours.<\P>
| Zone | City or Area Zone Crosses |
| GMT-12 | Eniwetok |
| GMT-11 | Samoa |
| GMT-10 | Hawaii |
| GMT-9 | Alaska |
| GMT-8 | PST, Pacific US |
| GMT-7 | MST, Mountain US |
| GMT-6 | CST, Central US |
| GMT-5 | EST, Eastern US |
| GMT-4 | Atlantic, Canada |
| GMT-3 | Brazilia, Buenos Aries |
| GMT-2 | Mid-Atlantic |
| GMT-1 | Cape Verdes |
| GMT | Greenwich Mean Time, Dublin |
| GMT+1 | Berlin, Rome |
| GMT+2 | Israel, Cairo |
| GMT+3 | Moscow, Kuwait |
| GMT+4 | Abu Dhabi, Muscat |
| GMT+5 | Islamabad, Karachi |
| GMT+6 | Almaty, Dhaka |
| GMT+7 | Bangkok, Jakarta |
| GMT+8 | Hong Kong, Beijing |
| GMT+9 | Tokyo, Osaka |
| GMT+10 | Sydney, Melbourne, Guam |
| GMT+11 | Magadan, Soloman Is. |
| GMT+12 | Fiji, Wellington, Auckland |