Climate averages 1991–2020

Shahrīār weather
in December.

A cool, fairly dry month: the joint 10th warmest and the joint 8th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 8.5°C Daytime mean, December
Average low -2.1°C Night-time mean, December
Rainfall 37 mm 7 days with ≥1 mm
Daylight 10 h Sunrise to sunset, per day
Every month in Shahrīār · average highYear overview

December is a cool month in Shahrīār: daytime highs average 8.5°C and nights cool to about -2.1°C. By daytime temperature it is the joint 10th warmest of the 12 months.

Expect about 37 mm of rain on roughly 7 days, which makes December a fairly dry month (the joint 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 48 min on an average December day.

The nearest other city in this atlas is Shahre Jadide Andisheh (4 km away). In December its highs average 8.3°C, about as warm as Shahrīār, with 37 mm of rain.

Among the 128 cities listed in Iran, Shahrīār ranks joint 79th of 128 for the warmest December highs and joint 59th of 128 for the driest December (rainfall, lowest first). The mean December high of those 128 cities is 10.9°C; Shahrīār is 2.5°C cooler than that mean.

From December to January, average highs fall by 2.2°C to 6.2°C, and monthly rainfall stays at 37 mm.

The annual picture

December in context

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. -10-50510152025303540 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly rainfall

Average total · mm
Average monthly rainfall totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 500

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Shahrīār climate table

1991–2020
Monthly climate averages for Shahrīār, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 6.2°C-5.0°C-5.0°C377.010.010 h
February 8.5°C-3.3°C-3.3°C407.810.911 h
March 14.0°C1.2°C1.2°C489.011.912 h
April 20.4°C6.8°C6.8°C427.713.113 h
May 26.8°C12.5°C12.5°C153.514.014 h
June 33.0°C18.3°C18.3°C2.70.714.515 h
July 35.9°C21.9°C21.9°C1.40.414.314 h
August 35.0°C21.0°C21.0°C1.70.213.514 h
September 30.3°C16.3°C16.3°C1.60.412.412 h
October 23.0°C10.2°C10.2°C142.811.311 h
November 13.9°C2.9°C2.9°C356.010.310 h
December, selected 8.5°C-2.1°C-2.1°C376.99.810 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

December in nearby cities

Distance from Shahrīār

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Shahrīār) is explained once on the Shahrīār year overview and on the Sources, method and limits page.

Karaj, Moḩammad Shahr and Shahre Jadide Andisheh lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.