Alborz Province

Garmdarreh, Iran Climate

NASA POWER reanalysis for the half-degree grid cell around Garmdarreh, 1991-2020; a grid cell is an area average and can differ from a thermometer in town by several degrees

The warmest month is July, with an average high of 38°C; the coldest is January, with an average low of -1°C. A normal year brings 267 mm of precipitation.

Temperature through the year

The normal daily high and low and the record for every date at Tehran-Mehrabad, since 1943. The line marks today.

Normal daily high and low temperature at Garmdarreh through the year, in °C, with the record for each date.-200204060JanFebMarAprMayJunJulAugSepOctNovDec
  • Normal low
  • Normal high
  • Record high
  • Record low

Normals for Sep 27

Normal high
30°C
Normal low
16°C
Record high
35°Cin 2019
Record low
13°Cin 1991
Chance of a wet day
14%
Daylight
11 h 59 min

Month by month

Averages for 1991-2020. Wet days have at least 1 mm of precipitation in the reanalysis. Each month links to its own page.

MonthAvg highAvg lowRecord highRecord lowPrecipitationWet days
January9°C-1°C21°C (2015)-13°C (1973)28 mm6.2
February12°C0°C24°C (2016)-10°C (1967)31 mm5.7
March17°C4°C30°C (2018)-9°C (1980)37 mm6.2
April23°C9°C33°C (2008)-3°C (2014)33 mm6.0
May29°C15°C37°C (2025)0°C (2010)16 mm3.1
June35°C20°C42°C (2015)12°C (1994)6 mm0.0
July38°C23°C43°C (1975)14°C (1968)6 mm0.0
August37°C23°C42°C (2024)14°C (1957)6 mm3.1
September32°C18°C39°C (1979)11°C (1955)12 mm3.0
October25°C13°C33°C (2002)2°C (1977)28 mm6.2
November16°C5°C27°C (2012)-7°C (1958)36 mm6.0
December11°C1°C21°C (2005)-11°C (2003)28 mm6.2
Year23°C11°C267 mm52

Precipitation

Rain and melted snow together. The chance of a wet day is the share of days with at least 1 mm of precipitation in the reanalysis.

267 mm in a normal year, most in March.

Chance of a wet day

The chance of at least 1 mm of precipitation in the reanalysis on each date at Garmdarreh, in percent.0102030JanFebMarAprMayJunJulAugSepOctNovDec
  • Chance of a wet day

Humidity and comfort

NASA POWER reanalysis, 1991-2020, for the grid cell around Garmdarreh.

Days with a mean dew point of 18°C or more are rare here in every month.

MonthDew pointHumidityDryComfortableHumidMuggyOppressiveMiserable
January-5°C57%100%0%0%0%0%0%
February-4°C54%100%0%0%0%0%0%
March-1°C50%100%0%0%0%0%0%
April2°C46%100%0%0%0%0%0%
May4°C37%100%0%0%0%0%0%
June4°C25%100%0%0%0%0%0%
July5°C23%100%0%0%0%0%0%
August4°C23%100%0%0%0%0%0%
September3°C27%100%0%0%0%0%0%
October2°C39%100%0%0%0%0%0%
November-1°C52%100%0%0%0%0%0%
December-3°C57%100%0%0%0%0%0%

Comfort is judged by the day's mean dew point: dry below 13°C, comfortable to 16°C, humid to 18°C, muggy to 21°C, oppressive to 24°C, miserable above.

Clouds

Average share of the sky covered, from satellite (CERES and GEWEX SRB) by way of NASA POWER, 1991-2020.

The clearest month is September, with the sky 27 percent covered on average; the cloudiest is April, at 62 percent.

Wind

The mean wind speed over the whole day, from the MERRA-2 reanalysis by way of NASA POWER. Gusts run well above it.

The windiest month is July, averaging 13.3 km/h at 10 meters (33 feet) above the ground.

Daylight and sunshine

The longest day is Jun 15, with 14 h 35 min of daylight; the shortest is Dec 17, with 9 h 44 min.

Hours of daylight at Garmdarreh through the year.0510152025JanFebMarAprMayJunJulAugSepOctNovDec
  • Day length

Solar energy

Average daily sunshine reaching the ground on a flat surface, in kilowatt-hours per square meter, clouds included.

Sunrise and sunset calendar

Month pages

The weather in Garmdarreh in each month, day by day.

What this means

A normal is the average of the thirty years 1991 to 2020, the period the World Meteorological Organization and NOAA use for comparison. It is an average, not a forecast: most days depart from it, and some by a long way.

A record is the highest or lowest value on the date in every year the station has reported, back to 1943. It rests on one station, so a neighbor a few miles away can hold different ones.

Cloud, humidity, wind and sunshine come from a reanalysis: a weather model run over the past with every observation fed in, averaged over a grid cell about 50 km across. It is consistent everywhere on Earth; it smooths local detail such as a lake shore or a valley.

More for this place

Nearby

Sources

Records: NOAA GHCN-Daily, station IR000407540, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.