Weather in Karaj

Rain is wet season runs from October to November, inside an annual total of 509 mm. The wettest month is November at 80 mm; the driest is June at 12 mm.

Karaj is in Iran at 35.8°N. The 2001–2020 NASA POWER daily record describes a continental climate with a wide temperature swing. July is the warmest month (average 20.6°C, high 27.0°C) and January is the coolest (average -5.7°C, low -10.4°C). On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are June, July, and August.

When Karaj gets wet

The wet season in Karaj starts in October and ends in November (October and November). November is the core of it at 80 mm. June is the other extreme, with 12 mm.

A rainy day here is a day with at least 1 mm in the NASA POWER series. November averages 11 such days; June averages 3.

Hot and cool months in Karaj

Monthly average highs run from -1.1°C in January to 27.0°C in July. Nights follow the same curve: -10.4°C in January and 14.3°C in July.

Mean high across all twelve months is 13.0°C and mean low is 2.1°C. These are 20-year grid averages, so a city station can read a few degrees warmer or cooler.

The calendar in Karaj

The year bottoms out in January. Plan for -10.4°C at night and -1.1°C in the afternoon. February: 0.5°C high, -8.8°C low, 48 mm rain, 76% humidity. In March, Karaj averages 6.1°C by day and -3.6°C at night, with 47 mm of rain. April brings 45 mm and 9 rainy days; temperatures run from 0.8°C to 11.7°C. May stands apart from the months beside it: 18.0°C / 5.8°C and 17 mm. June is the driest month, averaging only 12 mm across 3 rainy days. Highs sit near 24.1°C.

July is the warmest month. Afternoon highs average 27.0°C and nights settle near 14.3°C, with 17 mm of rain. August brings 21 mm and 4 rainy days; temperatures run from 13.6°C to 26.2°C. September stands apart from the months beside it: 21.8°C / 9.6°C and 44 mm. October is when the wet season typically starts in Karaj: highs near 14.8°C, and rainfall jumps to 77 mm (10 rainy days). By November the wet season is ending. Karaj still sees about 80 mm, but the next month is usually leaner. In December, Karaj averages 0.9°C by day and -7.9°C at night, with 54 mm of rain.

Best months to visit Karaj

The three months with the highest comfort score are June, July, and August: June (17.5°C average, 12 mm, 43% humidity); July (20.6°C average, 17 mm, 40% humidity); August (19.9°C average, 21 mm, 39% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you want the wet season itself — fewer crowds, greener landscape, heavier rain — aim at October–November instead of the score.

How Karaj compares inside Iran

Tehran is about 42 km away: Karaj is 10.0°C cooler than Tehran in its hottest month and 198 mm wetter over the year than Tehran. Tehran’s wettest month is November (45 mm) versus November here.

Isfahan is about 359 km away: Karaj is 8.2°C cooler than Isfahan in its hottest month and 345 mm wetter over the year than Isfahan. Isfahan’s wettest month is March (28 mm) versus November here.

Tabriz is about 487 km away: Karaj is 2.6°C cooler than Tabriz in its hottest month and 273 mm wetter over the year than Tabriz. Tabriz’s wettest month is April (44 mm) versus November here.