Events during a DST changeover are shortenend/extended by one hour

Example at https://jsfiddle.net/ocucLm98/

When timezone is set to “local” and the system timezone is “Europe/London”, events taking place during the DST changeover seem to be hidden.

In the example we have an event on October 29th (when time goes back one hour at 2am local time) from 00:00 UTC to 01:00 UTC, which translates locally from 01:00 BST to 01:00 GMT.

When timezone is set to “Europe/London” it places the event between 00:00 and 01:00. The beginning is an hour early, the end would be correct in this case. Could it be that using “local” takes additionally Date.getTimezoneOffset() into account and that skews the period?

[neroux]

@arshaw @acerix, no comment?

[urkle]

So google calendar fails horribly. I tested the gaining an hour scenario. And the UX just displays 24hours only… thus an event from 12:30 -> 1:30 EDT and 12:30 -> 1:30 EST look identical (for the gaining an hour scenario)

Their editing UI does not allow you at all to pick 1:30 EST (the extra hour). So I had to use a different program to create these events… Which was Calendar on OS X.

in OS X the UX visually is the same you can’t tell the difference from looking at it.

incorrect labels in the popover

but when editing they allow you to “sort of” set the other 1:30a, however it doesn’t appear to stick. 😦

So all varying degrees of “gee we never thought about it” even though a good half the world does DST.