My system (Gnome 3 on Debian Testing) is confused about the current time. When I run date the time is showing correctly but some applications are an hour behind the times. For instance, when I add an event to Gnome Calendar the event time shown in the calendar appointments will be the time I entered minus one hour.I've found out what the issue is but don't know how to solve it:$ date ; TZ=GMT date ; TZ=BST dateSun 30 Apr 11:25:37 BST 2017Sun 30 Apr 10:25:37 GMT 2017Sun 30 Apr 10:25:37 BST 2017The first two lines of the output are correct, the third is an hour behind. What I can't understand is why the BST time zone appears to be an hour behind while at the same time the current time is correct - and using BST.This may also be relevant:$ timedatectl status      Local time: Sun 2017-04-30 11:33:07 BST  Universal time: Sun 2017-04-30 10:33:07 UTC        RTC time: Sun 2017-04-30 10:33:07       Time zone: Europe/London (BST, +0100) Network time on: yesNTP synchronized: yes RTC in local TZ: noEditOutput of zdump /etc/localtime:$ zdump /etc/localtime/etc/localtime  Sun Apr 30 12:22:53 2017 BST$ date ; TZ=GMT date ; TZ=BST dateSun 30 Apr 12:22:53 BST 2017Sun 30 Apr 11:22:53 GMT 2017Sun 30 Apr 11:22:53 BST 2017
Is my BST time zone an hour behind?
linux;systemd;timezone
Complementing Gilles answer;  I am on the same time zone as the OP. Western European Time aka WET it is the official denomination; if memory does not fail me it was included for Portugal in the Unix timezones around 1996.https://en.wikipedia.org/wiki/Western_European_Time European Time (WET, UTC00:00) is a time zone covering parts of  western and northwestern Europe.The following countries and regions use WET in winter months:  - Canary Islands, > since 1946 (rest of Spain is CET, UTC+1)  - Faroe Islands, since 1908  - North Eastern Greenland (Danmarkshavn and surrounding area)  - Iceland, since 1968  - Portugal, since 1912 with pauses (except Azores, UTC1)[1]  - Madeira Islands, since 1912 with pauses[2]  - Ireland, since 1916 (legally known as Greenwich Mean Time) except between 1968 and 1971  - United Kingdom and Crown dependencies, since 1847 in England, Scotland, Wales, the Channel Islands, and the Isle of Man, and since 1916 in Northern Ireland (legally known as Greenwich Mean Time), with pauses In the United Kingdom, from 1940 to 1945 British Summer Time (BST=CET)  was used in winters, and from 1941 to 1945 and again in 1947, British  Double Summer Time (BDST=CEST) was used in summers. Between 18  February 1968 and 31 October 1971, BST was used all year round.All the above countries except Iceland implement daylight saving time  in summer, switching to Western European Summer Time (WEST, UTC+1),  which is one hour ahead of WET. WEST is called British Summer Time in  the UK and is officially known as Irish Standard Time in Ireland.While the official denomination for the summer time is WEST (Western European Summer Time), WETis used for TZ,  and takes in account summer time/DST, advancing one hour.'Europe/London' might be nowadays a better choice, however knowing the WET shorthand is still useful in some situations.https://en.wikipedia.org/wiki/List_of_tz_database_time_zonesSo, to compare results with your initial test:$date ; TZ=GMT date ; TZ=WET dateMon May  1 09:36:10 WEST 2017Mon May  1 08:36:10 GMT 2017Mon May  1 09:36:10 WEST 2017