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 99°F, while the coldest is January averaging around 30°F at night. Precipitation totals about 9 inches a year and is strongly seasonal — April alone averages 1.4 inches while September barely receives 0.17 inches.

☀️ Summers

Very hot

Highs near 99°F in July.

About 74 days a year above 90 °F

❄️ Winters

Cold

Lows near 30°F in January.

About 15 freezing nights a year

🌧️ Rain

Very dry

About 9 in of rain a year.

Wettest in April

⛅ Sky & trend

Fairly sunny

More sun than cloud through the year.

+5.7 °F vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures

Clear vs cloudy days

Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day counts

Karaj climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	48	53	63	73	84	95	99	97	90	77	61	52
Avg temp (°F)	39	42	51	61	71	81	87	86	77	68	53	43
Avg low (°F)	30	32	39	49	58	68	74	76	65	58	45	34
Precipitation (in)	1.2	1.3	1.3	1.4	0.5	0.3	0.3	0.2	0.2	0.5	1.1	1.0

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°F)	48	53	63	73	84	95
Avg temp (°F)	39	42	51	61	71	81
Avg low (°F)	30	32	39	49	58	68
Precipitation (in)	1.2	1.3	1.3	1.4	0.5	0.3

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	99	97	90	77	61	52
Avg temp (°F)	87	86	77	68	53	43
Avg low (°F)	74	76	65	58	45	34
Precipitation (in)	0.3	0.2	0.2	0.5	1.1	1.0

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 ≥ 90°F (days)	—	—	—	0.3	4	17	21	20	12	0.7	—	—
Days with low ≤ 32°F (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 ≥ 90°F (days)	—	—	—	0.3	4	17
Days with low ≤ 32°F (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 ≥ 90°F (days)	21	20	12	0.7	—	—
Days with low ≤ 32°F (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.

How we build these numbers →