Does London observe daylight saving time?

Yes. London is on BST (UTC+1) now, and its clocks go back 1 hour on Sun, Oct 25, to GMT (UTC+0).

Does Tehran observe daylight saving time?

No. Tehran stays on IRST (UTC+3:30) all year, so its clocks don't change.

What time is it in Tehran when it's 9 AM in London?

11:30 AM in Tehran, on the same day.

London to Tehran Meeting Planner

Tehran is 2 hours 30 minutes ahead of London right now. Their working days overlap for 5 hours 30 minutes today.

London · United Kingdom

3:35 AM

Sun, Oct 18 · BST · summer time

Tehran · Iran

6:05 AM

Sun, Oct 18 · IRST

Best Meeting Times Between London and Tehran

9:00 AM to 2:30 PM in London (11:30 AM to 5:00 PM in Tehran). That's when both cities are inside working hours, 9 AM to 5 PM, giving 5 hours 30 minutes of overlap today.

Who's meeting

2 of 4 places

LondonOrganizerUnited Kingdom ·· summer time3:35AMnow
TehranIran ·6:05AMnow

Add a city

Add up to 4 places by city, country, time zone or abbreviation, like Tokyo, India or JST. Press "/" to jump here.

Date in London

Working hours, everywhere

Best times to meet

Sunday, October 18, 2026, in London time.

1:00PMBest · OptimalWorking hours in London (13:00) and Tehran (15:30).
12:30PMOption 2 · OptimalWorking hours in London (12:30) and Tehran (15:00).
1:30PMOption 3 · OptimalWorking hours in London (13:30) and Tehran (16:00).

The whole day

Pick any slot in the Fit row, or use the arrow keys there, to make it the meeting time.

Each column is a half hour of the first place's day. The Fit row grades how well the slot suits everyone; each row shows the local time and whether it's working hours there.
Fit
LondonBST
TehranUTC+3:30
UTC	23	00	01	02	03	04	05	06	07	08	09	10	11	12	13	14	15	16	17	18	19	20	21	22

Working hours (09–17)Just outside (07–09, 17–20)Late evening (20–23)NightFit: optimal, good, possible, poor

Your meeting

London1:00 PM BSTSun, Oct 18
Tehran3:30 PM UTC+3:30Sun, Oct 18
UTC2026-10-18 12:00 UTC

What will it cost? Try the meeting cost calculator.

Time difference between London and Tehran

Tehran is 2 hours 30 minutes ahead of London right now: Tehran is on IRST (UTC+3:30) and London on BST (UTC+1). That changes on Sun, Oct 25, when clocks go back in London: then Tehran is 3 hours 30 minutes ahead of London.

Time difference between London and Tehran over the next 12 months
From	Difference	Why
Now	Tehran 2 hours 30 minutes ahead	—
Sun, Oct 25	Tehran 3 hours 30 minutes ahead	Clocks go back in London
Sun, Mar 28, 2027	Tehran 2 hours 30 minutes ahead	Clocks go forward in London

London is on Greenwich Mean Time. Tehran is on Iran Standard Time.

Frequently Asked Questions: London & Tehran Scheduling

What is the time difference between London and Tehran?: Tehran is 2 hours 30 minutes ahead of London right now: Tehran is on IRST (UTC+3:30) and London on BST (UTC+1). That changes on Sun, Oct 25, when clocks go back in London: then Tehran is 3 hours 30 minutes ahead of London.
What is the best time to schedule a meeting between London and Tehran?: 9:00 AM to 2:30 PM in London (11:30 AM to 5:00 PM in Tehran). That's when both cities are inside working hours, 9 AM to 5 PM, giving 5 hours 30 minutes of overlap today.
Does London observe daylight saving time?: Yes. London is on BST (UTC+1) now, and its clocks go back 1 hour on Sun, Oct 25, to GMT (UTC+0).
Does Tehran observe daylight saving time?: No. Tehran stays on IRST (UTC+3:30) all year, so its clocks don't change.
What time is it in Tehran when it's 9 AM in London?: 11:30 AM in Tehran, on the same day.

Or see every city pair, or plan with more places in the meeting planner.