Frost dates in Tehran: last spring frost and first autumn frost
When is it safe to plant out in Tehran, and when does the first frost come? Dates from 45 years of nightly minimum temperatures (1981–2025), with how early or late they can fall.
Frost dates in Tehran and how sure they are
| Early year (1 in 10) | Typical (median) | Late year (1 in 10) | |
|---|---|---|---|
| Last spring frost | 28 February | 19 March | 3 April |
| First autumn frost | 14 November | 29 November | 16 December |
In a typical year the last frost in Tehran falls around 19 March and the first one around 29 November, leaving about 261 frost-free days (between 233 and 274 in 8 years out of 10). To be safe, plant tender crops after 3 April: by then the last frost has passed in 9 years out of 10. Bring them in before 14 November: in 1 year in 10 the first frost comes earlier.
Frost month by month in Tehran
| Month | Average low | Coldest night (avg) | Record low | Frost nights | Years with frost |
|---|---|---|---|---|---|
| January | -0.9 °C | -5.6 °C | -13.8 °C | 19.6 | 100% |
| February | -0.1 °C | -5.2 °C | -9.9 °C | 14.6 | 100% |
| March | 3.6 °C | -2.7 °C | -7.5 °C | 5.1 | 87% |
| April | 9.4 °C | 2.3 °C | -2.5 °C | 0.2 | 16% |
| May | 14.5 °C | 8.9 °C | 2.3 °C | 0 | 0% |
| June | 20 °C | 15.5 °C | 12 °C | 0 | 0% |
| July | 23.1 °C | 19.7 °C | 15.6 °C | 0 | 0% |
| August | 22.4 °C | 19.1 °C | 14.4 °C | 0 | 0% |
| September | 18.1 °C | 13.4 °C | 9.1 °C | 0 | 0% |
| October | 12.1 °C | 7.2 °C | 1.7 °C | 0 | 0% |
| November | 5.4 °C | -0.5 °C | -13.6 °C | 2.1 | 51% |
| December | 0.9 °C | -3.7 °C | -7.7 °C | 12.4 | 98% |
Frost here means a night minimum at or below 0 °C at 2 m. Frost nights is the average count per month; years with frost is how many years had at least one.
Frost alerts for your garden or field
LayEarth Business Agro sends an alert when the forecast low at your saved site drops below your threshold (0 °C by default), with frost risk, hours below zero and white or black frost for each forecast day. LayEarth Pro, from 9 USD a month, adds alerts for the places you follow.
Temperature map around Tehran
The live temperature layer of the map (NOAA GFS forecast): watch the cold nights coming hour by hour.
More for Tehran
Weather in Tehran now · Will it rain today in Tehran? · Open the temperature map on Tehran
Questions
- When is the last frost in Tehran?
- On average around 19 March. In an early year the last frost comes by 28 February, in a late one (1 year in 10) after 3 April.
- When is the first frost in Tehran?
- On average around 29 November. In 1 year in 10 it comes before 14 November, in a mild year not until 16 December.
- How long is the growing season in Tehran?
- About 261 frost-free days between the last spring frost and the first autumn frost, from 233 in a short year to 274 in a long one.
- When can I plant tomatoes in Tehran?
- Frost-tender plants such as tomatoes, peppers, beans and courgettes go out after the last frost: after 3 April the risk is down to 1 year in 10. Hardy crops can go earlier.
- How cold does it get in Tehran?
- The coldest night of winter averages -6.9 °C; the lowest since 1981 was -13.8 °C in 2008.
Frost dates nearby
How these dates are computed
Daily minimum temperature at 2 m from NASA POWER (MERRA-2 reanalysis, public domain), 1981–2025, corrected from the ~50 km grid to the real altitude of Tehran (6.5 °C per km). For each year: the last night at or below 0 °C before midsummer and the first one after it; the dates are the median and the 10% / 90% of those years. A garden in a frost pocket or a city centre can differ by days. Live temperatures: the temperature layer of the map.