Timezone select to use daylight saving

Teach

Hi there!
I'm currently using this select menu, which is made pretty simply and works very effectively, however, as it doesn't use daylight saving times, for a few months of the year the times it shows would be wrong. Is there a way you can help me update it to take that into consideration?


echo "<option value='GMT -12:00' ". ($frm23=="GMT -12:00" ? "selected='selected'" : "").">(GMT -12:00) Eniwetok, Kwajalein [".date('D M d H:i', time() - (60*60*12))."]</option>\n";
echo "<option value='GMT -11:00' ". ($frm23=="GMT -11:00" ? "selected='selected'" : "").">(GMT -11:00) Midway Island, Samoa [".date('D M d H:i', time() - (60*60*11))."]</option>\n";
echo "<option value='GMT -10:00' ". ($frm23=="GMT -10:00" ? "selected='selected'" : "").">(GMT -10:00) Hawaii [".date('D M d H:i', time() - (60*60*10))."]</option>\n";
echo "<option value='GMT -9:00' ". ($frm23=="GMT -9:00" ? "selected='selected'" : "").">(GMT -9:00) Alaska [".date('D M d H:i', time() - (60*60*9))."]</option>\n";
echo "<option value='GMT -8:00' ". ($frm23=="GMT -8:00" ? "selected='selected'" : "").">(GMT -8:00) Pacific Time (US &amp; Canada) [".date('D M d H:i', time() - (60*60*8))."]</option>\n";
echo "<option value='GMT -7:00' ". ($frm23=="GMT -7:00" ? "selected='selected'" : "").">(GMT -7:00) Mountain Time (US &amp; Canada) [".date('D M d H:i', time() - (60*60*7))."]</option>\n";
echo "<option value='GMT -6:00' ". ($frm23=="GMT -6:00" ? "selected='selected'" : "").">(GMT -6:00) Central Time (US &amp; Canada), Mexico City [".date('D M d H:i', time() - (60*60*6))."]</option>\n";
echo "<option value='GMT -5:00' ". ($frm23=="GMT -5:00" ? "selected='selected'" : "").">(GMT -5:00) Eastern Time (US &amp; Canada), Bogota, Lima [".date('D M d H:i', time() - (60*60*5))."]</option>\n";
echo "<option value='GMT -4:00' ". ($frm23=="GMT -4:00" ? "selected='selected'" : "").">(GMT -4:00) Atlantic Time (Canada), Caracas, La Paz [".date('D M d H:i', time() - (60*60*4))."]</option>\n";
echo "<option value='GMT -3:5' ". ($frm23=="GMT -3:5" ? "selected='selected'" : "").">(GMT -3:30) Newfoundland [".date('D M d H:i', time() - (60*60*3.5))."]</option>\n";
echo "<option value='GMT -3:00' ". ($frm23=="GMT -3:00" ? "selected='selected'" : "").">(GMT -3:00) Brazil, Buenos Aires, Georgetown [".date('D M d H:i', time() - (60*60*3))."]</option>\n";
echo "<option value='GMT -2:00' ". ($frm23=="GMT -2:00" ? "selected='selected'" : "").">(GMT -2:00) Mid-Atlantic [".date('D M d H:i', time() - (60*60*2))."]</option>\n";
echo "<option value='GMT -1:00' ". ($frm23=="GMT -1:00" ? "selected='selected'" : "").">(GMT -1:00) Azores, Cape Verde Islands [".date('D M d H:i', time() - (60*60*1))."]</option>\n";
echo "<option value='GMT' ". ($frm23=="GMT" ? "selected='selected'" : "").">(GMT) Western Europe Time, London, Lisbon, Casablanca [".date('D M d H:i')."]</option>\n";
echo "<option value='GMT +1:00' ". ($frm23=="GMT +1:00" ? "selected='selected'" : "").">(GMT +1:00) Brussels, Copenhagen, Madrid, Paris [".date('D M d H:i', time() + (60*60*1))."]</option>\n";
echo "<option value='GMT +2:00' ". ($frm23=="GMT +2:00" ? "selected='selected'" : "").">(GMT +2:00) Kaliningrad, South Africa, Bucharest [".date('D M d H:i', time() + (60*60*2))."]</option>\n";
echo "<option value='GMT +3:00' ". ($frm23=="GMT +3:00" ? "selected='selected'" : "").">(GMT +3:00) Baghdad, Riyadh, Moscow, St. Petersburg [".date('D M d H:i', time() + (60*60*3))."]</option>\n";
echo "<option value='GMT +3:5' ". ($frm23=="GMT +3:5" ? "selected='selected'" : "").">(GMT +3:30) Tehran [".date('D M d H:i', time() + (60*60*3.5))."]</option>\n";
echo "<option value='GMT +4:00' ". ($frm23=="GMT +4:00" ? "selected='selected'" : "").">(GMT +4:00) Abu Dhabi, Muscat, Baku, Tbilisi [".date('D M d H:i', time() + (60*60*4))."]</option>\n";
echo "<option value='GMT +4:5' ". ($frm23=="GMT +4:5" ? "selected='selected'" : "").">(GMT +4:30) Kabul [".date('D M d H:i', time() + (60*60*4.5))."]</option>\n";
echo "<option value='GMT +5:00' ". ($frm23=="GMT +5:00" ? "selected='selected'" : "").">(GMT +5:00) Ekaterinburg, Islamabad, Karachi, Tashkent [".date('D M d H:i', time() + (60*60*5))."]</option>\n";
echo "<option value='GMT +5:5' ". ($frm23=="GMT +5:5" ? "selected='selected'" : "").">(GMT +5:30) Bombay, Calcutta, Madras, New Delhi [".date('D M d H:i', time() + (60*60*5.5))."]</option>\n";
echo "<option value='GMT +6:00' ". ($frm23=="GMT +6:00" ? "selected='selected'" : "").">(GMT +6:00) Almaty, Dhaka, Colombo [".date('D M d H:i', time() + (60*60*6))."]</option>\n";
echo "<option value='GMT +7:00' ". ($frm23=="GMT +7:00" ? "selected='selected'" : "").">(GMT +7:00) Bangkok, Hanoi, Jakarta [".date('D M d H:i', time() + (60*60*7))."]</option>\n";
echo "<option value='GMT +8:00' ". ($frm23=="GMT +8:00" ? "selected='selected'" : "").">(GMT +8:00) Beijing, Perth, Singapore, Hong Kong [".date('D M d H:i', time() + (60*60*8))."]</option>\n";
echo "<option value='GMT +9:00' ". ($frm23=="GMT +9:00" ? "selected='selected'" : "").">(GMT +9:00) Tokyo, Seoul, Osaka, Sapporo, Yakutsk [".date('D M d H:i', time() + (60*60*9))."]</option>\n";
echo "<option value='GMT +9.5' ". ($frm23=="GMT +9.5" ? "selected='selected'" : "").">(GMT +9:30) Adelaide, Darwin [".date('D M d H:i', time() + (60*60*9.5))."]</option>\n";
echo "<option value='GMT +10:00' ". ($frm23=="GMT +10:00" ? "selected='selected'" : "").">(GMT +10:00) Eastern Australia, Guam, Vladivostok [".date('D M d H:i', time() + (60*60*10))."]</option>\n";
echo "<option value='GMT +11:00' ". ($frm23=="GMT +11:00" ? "selected='selected'" : "").">(GMT +11:00) Magadan, Solomon Islands, New Caledonia [".date('D M d H:i', time() + (60*60*11))."]</option>\n";
echo "<option value='GMT +12:00' ". ($frm23=="GMT +12:00" ? "selected='selected'" : "").">(GMT +12:00) Auckland, Wellington, Fiji, Kamchatka [".date('D M d H:i', time() + (60*60*12))."]</option>\n";

Thanks!

Kudose

I am pretty sure PHP has nothing to do with the time. The server keeps track of that for PHP.

Teach

Hi there - thanks for your reply.

Yep, I know that - and the GMT (as we're hosted in the UK) will always be right even on daylight saving as that's the local time. What I mean is for the other times to have that taken into consideration. Let's say the GMT clock goes foward one hour, then those that normally have say .. +6 would only need +5

Hope this makes sense 🙂

Weedpacket

UTC doesn't do daylight saving. If you base your time calculations off that that instead of server local time then that's two daylight saving transitions you don't have to worry about.

(The UK public doesn't use Greenwich Mean Time. (a) Greenwich Mean Time didn't do daylight saving either (that's why it was called "Mean" time), and (b) GMT was deprecated in the early 1970s in favour of UTC. UK standard time is UTC+00:00 and Summer time is UTC+01:00.
As the US Naval Observatory notes, "Greenwich Mean Time is a widely used historical term, but one that has been used in several ways. Because of the ambiguity, its use is no longer recommended in technical contexts." And this is a technical context.)

Teach

Thanks for that reply Weedpacket!
Tried looking at how to base it on UTC instead of just time() but cannot find such information.

Would you mind letting me know how to do that? Thanks!

ClarkF1

date("I"); will return 1 if the server time zone is currently in Daylight Savings Time and 0 if it isn't.

If using time(), just add 3600 * date("I") to the time e.g.

$time = time() + 3600 * date("I");

3600 is the number of seconds in an hour