BST stands for British Summer Time. It is the timezone the United Kingdom uses during summer months, when clocks move forward by one hour from GMT (Greenwich Mean Time).

GMT (Greenwich Mean Time) = UTC+0 — used in UK winter
BST (British Summer Time) = UTC+1 — used in UK summer

When Does BST Start and End?

Clocks go forward (winter → summer) on the last Sunday in March at 1:00am — 1:00am becomes 2:00am. Clocks go back (summer → winter) on the last Sunday in October at 2:00am — 2:00am becomes 1:00am.

2026 dates: BST starts on Sunday 29 March 2026 at 1:00am. BST ends on Sunday 25 October 2026 at 2:00am.

GMT vs BST: What Changes

When the UK moves from GMT to BST, it moves from UTC+0 to UTC+1. This means sunrise and sunset are both one hour later by the clock, the UK is one hour closer to Europe (which also moves to summer time around the same period), and the UK is one hour further from countries that don't observe DST (like Singapore, Dubai, Japan, India).

How BST Affects International Calls

BST has a direct effect on the time difference between the UK and other countries. New York (EDT) is 5 hours behind in both GMT and BST. Singapore is 8 hours ahead of GMT but only 7 hours ahead during BST. Dubai is 4 hours ahead of GMT but 3 hours ahead during BST. India is 5.5 hours ahead of GMT but 4.5 hours ahead during BST. Sydney (AEST) is 10 hours ahead of GMT but 9 hours ahead during BST.

Note: The US and UK move clocks at slightly different times, so the NY–London gap briefly becomes 4 or 6 hours during the transition weeks.

BST vs CEST: Is the UK in Sync with Europe During Summer?

The EU uses CEST (Central European Summer Time) = UTC+2. The UK on BST (UTC+1) is always 1 hour behind continental Europe, in both summer and winter. The gap doesn't change seasonally.

Common BST Confusion

"Is it GMT or BST right now?" If it's between late March and late October, the UK is on BST. Otherwise, GMT.

"Do all UK territories use BST?" No. The Channel Islands use BST. But some Crown Dependencies observe their own rules. Internationally, only Great Britain and Northern Ireland officially use BST — other parts of the British Isles have their own designations.

Why This Matters for Scheduling

Every clock change in the UK shifts the time difference with non-DST countries by one hour. If you have recurring calls with people in Singapore, Dubai, India, or Japan, their time on your calendar shifts by an hour when the UK changes its clocks — even though nothing changed on their end. This is one of the most common sources of scheduling errors in international remote work.

Wenya handles BST/GMT transitions automatically in scheduling proposals, so both parties always see the correct local time.