Karaj, Iran climate
BSk Cold semi-arid
Karaj has a strongly seasonal mild-temperate climate (Cold semi-arid, Köppen BSk). The hottest month is July with an average daily high near 37°C, while the coldest is January averaging around −1°C at night. Precipitation totals about 235 mm a year and is strongly seasonal — April alone averages 36 mm while September barely receives 4 mm.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsKaraj climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 9 | 12 | 17 | 23 | 29 | 35 | 37 | 36 | 32 | 25 | 16 | 11 |
| Avg temp (°C) | 4 | 6 | 11 | 16 | 22 | 27 | 30 | 30 | 25 | 20 | 12 | 6 |
| Avg low (°C) | −1 | 0 | 4 | 9 | 15 | 20 | 23 | 24 | 18 | 15 | 7 | 1 |
| Precipitation (mm) | 30 | 33 | 34 | 36 | 12 | 8 | 7 | 5 | 4 | 13 | 29 | 25 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 9 | 12 | 17 | 23 | 29 | 35 |
| Avg temp (°C) | 4 | 6 | 11 | 16 | 22 | 27 |
| Avg low (°C) | −1 | 0 | 4 | 9 | 15 | 20 |
| Precipitation (mm) | 30 | 33 | 34 | 36 | 12 | 8 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 37 | 36 | 32 | 25 | 16 | 11 |
| Avg temp (°C) | 30 | 30 | 25 | 20 | 12 | 6 |
| Avg low (°C) | 23 | 24 | 18 | 15 | 7 | 1 |
| Precipitation (mm) | 7 | 5 | 4 | 13 | 29 | 25 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 5 | 6 | 6 | 7 | 4 | 1 | 0.9 | 0.5 | 0.7 | 3 | 5 | 5 |
| Days with high ≥ 32°C (days) | — | — | — | 0.3 | 4 | 17 | 21 | 20 | 12 | 0.7 | — | — |
| Days with low ≤ 0°C (days) | 7 | 4 | 0.8 | 0.1 | 0.0 | — | — | — | — | — | 0.5 | 3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 5 | 6 | 6 | 7 | 4 | 1 |
| Days with high ≥ 32°C (days) | — | — | — | 0.3 | 4 | 17 |
| Days with low ≤ 0°C (days) | 7 | 4 | 0.8 | 0.1 | 0.0 | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 0.9 | 0.5 | 0.7 | 3 | 5 | 5 |
| Days with high ≥ 32°C (days) | 21 | 20 | 12 | 0.7 | — | — |
| Days with low ≤ 0°C (days) | — | — | — | — | 0.5 | 3 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 56 | 58 | 61 | 62 | 52 | 36 | 36 | 29 | 27 | 40 | 52 | 55 |
| Clear days (≤ 30% cloud) | 5 | 3 | 3 | 3 | 7 | 14 | 14 | 20 | 21 | 15 | 9 | 7 |
| Partly cloudy days (30–70%) | 17 | 16 | 16 | 15 | 16 | 14 | 14 | 10 | 7 | 11 | 11 | 14 |
| Cloudy days (≥ 70%) | 9 | 9 | 12 | 12 | 8 | 2 | 2 | 1 | 1 | 5 | 10 | 10 |
| Relative humidity (%) | 57 | 54 | 50 | 45 | 37 | 25 | 23 | 23 | 27 | 39 | 52 | 57 |
| Wind speed (mph) | 4.0 | 4.7 | 5.1 | 5.2 | 5.3 | 5.7 | 6.0 | 5.4 | 4.8 | 4.3 | 3.8 | 3.5 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 56 | 58 | 61 | 62 | 52 | 36 |
| Clear days (≤ 30% cloud) | 5 | 3 | 3 | 3 | 7 | 14 |
| Partly cloudy days (30–70%) | 17 | 16 | 16 | 15 | 16 | 14 |
| Cloudy days (≥ 70%) | 9 | 9 | 12 | 12 | 8 | 2 |
| Relative humidity (%) | 57 | 54 | 50 | 45 | 37 | 25 |
| Wind speed (mph) | 4.0 | 4.7 | 5.1 | 5.2 | 5.3 | 5.7 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 36 | 29 | 27 | 40 | 52 | 55 |
| Clear days (≤ 30% cloud) | 14 | 20 | 21 | 15 | 9 | 7 |
| Partly cloudy days (30–70%) | 14 | 10 | 7 | 11 | 11 | 14 |
| Cloudy days (≥ 70%) | 2 | 1 | 1 | 5 | 10 | 10 |
| Relative humidity (%) | 23 | 23 | 27 | 39 | 52 | 57 |
| Wind speed (mph) | 6.0 | 5.4 | 4.8 | 4.3 | 3.8 | 3.5 |
Methodology & sources
Temperature — modelled for this location from ERA5-Land reanalysis, a ~9 km global grid, because no long-record weather station is close enough to use.
Precipitation — 1991–2020 normals computed from 26 years of daily observations at Tehran-mehrabad, a weather station, about 34 km from the city centre. The underlying daily records come from NOAA's global station network.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.