The Time Zone Problem

Time zones and the British perspective
San Francisco (Where Linden Labs are based) has Pacific Daylight Time (PDT) and the United Kingdom has Greenwich Mean Time (GMT). Normally, PDT is eight hours behind GMT. So, if it’s 6.00pm in the UK, then it’s 10.00am in San Francisco. Except when it isn’t, which is usually for two or three weeks each spring and one week each autumn.

Both places move forward an hour each spring and back an hour each autumn (spring forward, fall back). Even if both places did that on the same day each year you would still need to know about it, because the shift would take place at different times in each place. We would still be out of synch, but only for a maximum of eight hours instead of days or weeks.

SPRING
In spring, the USA tends to adopt Daylight Saving Time (DST) a couple of weeks before the UK moves to British Summer Time (BST). So, during the interval, if you’re in the UK and you’re attending an event in Second Life, you have to show up an hour EARLIER, because, for a couple (or three) weeks the time zone difference between the two places is seven hours.

In the year 2019
PDT gains DST on Sunday 10th March
GMT goes to BST on Sunday 31st March

In the year 2020
PDT gains DST on Sunday 8th March
GMT goes to BST on Sunday 29th March

In the year 2021
PDT gains DST on Sunday 14th March
GMT goes to BST on Sunday 28th March

AUTUMN (FALL, WHATEVER)
In autumn the UK reverts to GMT a week or so before San Francisco goes back to PDT. During that interval, if you’re in the UK and you attend an event in Second Life, you can show up an hour LATER, because for that short period the time zone difference is nine hours.

In the year 2019
BST goes to GMT on Sunday 27th October
PDT loses DST on Sunday 7th November

In the year 2020
BST goes to GMT on Sunday 25th October
PDT loses DST on Sunday 1st November

In the year 2021
BST goes to GMT on Sunday 31st October
PDT loses DST on Sunday 7th November

If the event is on the date when the USA changes, tread carefully (or cancel your plans and have a day off), because both the USA and UK change in either direction at 2.00am local time. Basically, as far as the UK is concerned, the changes in SL take place at 10.00am on Sunday.