A Persian chat room is one of the few places where someone finishing dinner in Tehran, someone leaving work in Vienna and someone drinking a first coffee in Los Angeles are all in the same conversation. Knowing who is awake when makes it much easier to find the people you want to talk to.
The clocks that matter
Iran uses a single time zone, three and a half hours ahead of Coordinated Universal Time (UTC+3:30). The half hour surprises many people; Afghanistan has one too, at UTC+4:30. Iran stopped changing its clocks for summer after 2022, so Tehran time is now the same all year. Europe and most of North America still move their clocks, which means the distance to Tehran changes twice a year.
| City | Winter | Summer | Compared with Tehran |
|---|---|---|---|
| Tehran | UTC+3:30 | UTC+3:30 | — |
| Kabul | UTC+4:30 | UTC+4:30 | 1 hour ahead |
| Dubai | UTC+4 | UTC+4 | 30 minutes ahead |
| Istanbul | UTC+3 | UTC+3 | 30 minutes behind |
| Vienna, Berlin, Stockholm, Paris | UTC+1 | UTC+2 | 2½ hours behind in winter, 1½ in summer |
| London | UTC+0 | UTC+1 | 3½ hours behind in winter, 2½ in summer |
| Toronto, New York | UTC−5 | UTC−4 | 8½ hours behind in winter, 7½ in summer |
| Los Angeles | UTC−8 | UTC−7 | 11½ hours behind in winter, 10½ in summer |
| Vancouver | UTC−7 | UTC−7 | 10½ hours behind all year |
Vancouver used to keep the same time as Los Angeles. Since March 2026 most of British Columbia no longer changes its clocks and stays on UTC−7 all year, so in winter Vancouver is now one hour ahead of Los Angeles.
"Winter" and "summer" here mean the northern seasons. Australia is the other way round: Sydney is on UTC+11 during the northern winter and UTC+10 during the northern summer, six and a half to seven and a half hours ahead of Tehran.
What 9 pm in Tehran looks like elsewhere
Evening is when chat rooms are busiest. Here is the same moment around the world, in the northern winter:
| City | Local time | What people are doing |
|---|---|---|
| Kabul | 10:00 pm | Late evening |
| Tehran | 9:00 pm | After dinner |
| Vienna, Berlin | 6:30 pm | Home from work |
| London | 5:30 pm | Leaving work |
| Toronto, New York | 12:30 pm | Lunch break |
| Vancouver | 10:30 am | Morning |
| Los Angeles | 9:30 am | Morning |
| Sydney | 4:30 am (next day) | Asleep |
In the northern summer, add one hour to the rows for Europe, Toronto, New York and Los Angeles, and subtract one from Sydney. Kabul, Tehran and Vancouver stay as they are.
The best overlaps
Iran and Europe. This is the easiest pair. Evenings almost coincide: from about 6 pm to 10 pm Central European time, both sides are awake and free. This is why European evenings are the liveliest hours in most Persian rooms.
Iran and the east coast of North America. The window is the North American morning and lunch hour, which is evening and late night in Tehran. Weekend mornings in Toronto or New York are ideal.
Iran and the west coast. The gap is nearly half a day. Early morning in Los Angeles, around 7 to 9 am, reaches Tehran's evening. Late evening in Los Angeles, after 9 pm, reaches Tehran's next morning.
Europe and North America. European evening is North American afternoon, which is why rooms often get a second wave of activity late at night in Europe as people on the other side of the Atlantic finish work.
The two confusing weeks
Europe and North America do not change their clocks on the same day. Europe changes on the last Sunday of March and of October; the United States and most of Canada change on the second Sunday of March and the first Sunday of November. For two or three weeks in spring and about one week in autumn, the usual differences are off by an hour. If a regular call suddenly starts at the wrong time in March, this is the reason.
Weekends are not the same everywhere
In Iran the weekly day of rest is Friday, and Thursday is a short day for many people. In Europe and the Americas the weekend is Saturday and Sunday. A relaxed Friday evening in Tehran is an ordinary working afternoon in Vienna, and a lazy Sunday morning in Toronto is a working day in Tehran. Friday and Saturday evenings, European time, tend to be when both rhythms overlap best.
Practical habits
- When you arrange to talk, name the city: "9 pm Vienna time", not just "9 pm".
- Add a second clock for Tehran or Toronto to your phone's clock app. It takes ten seconds and ends the mental arithmetic.
- If someone answers briefly, check the time where they are. They may be at work or half asleep.
- Leave a message if the person is offline. In Asal Chat, private messages to members who are away are kept for them until they return.
The time difference is a small nuisance for scheduling and a quiet pleasure for conversation: there is nearly always someone, somewhere, for whom it is the right hour to talk.