Climate averages 1991–2020

Mission weather
in December.

A warm, fairly dry month: the 11th warmest and the 3rd driest of the year. Meets the pleasant-weather rule

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

Average high 22.5°C Daytime mean, December
Average low 12.9°C Night-time mean, December
Rainfall 30 mm 5 days with ≥1 mm
Daylight 11 h Sunrise to sunset, per day
Every month in Mission · average highYear overview

December is a warm month in Mission: daytime highs average 22.5°C and nights cool to about 12.9°C. By daytime temperature it is the 11th warmest of the 12 months.

Expect about 30 mm of rain on roughly 5 days, which makes December a fairly dry month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 10 h 32 min on an average December day.

The nearest other city in this atlas is McAllen (10 km away). In December its highs average 22.5°C, about as warm as Mission, with 30 mm of rain.

Among the 498 cities listed in the United States, Mission ranks joint 21st of 498 for the warmest December highs and joint 47th of 498 for the driest December (rainfall, lowest first). The mean December high of those 498 cities is 10.5°C; Mission is 12.0°C warmer than that mean.

From December to January, average highs fall by 0.7°C to 21.9°C, and monthly rainfall falls from 30 mm to 26 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. 510152025303540 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 1000

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

Every month, side by side

Mission climate table

1991–2020
Monthly climate averages for Mission, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 21.9°C12.0°C12.0°C264.410.711 h
February 24.5°C14.0°C14.0°C244.411.311 h
March 27.5°C16.8°C16.8°C365.212.012 h
April 30.7°C19.9°C19.9°C445.312.813 h
May 33.2°C23.0°C23.0°C556.613.413 h
June 35.2°C25.1°C25.1°C517.013.814 h
July 35.8°C25.5°C25.5°C555.713.614 h
August 36.1°C25.7°C25.7°C396.713.113 h
September 32.7°C23.8°C23.8°C8811.812.312 h
October 30.2°C20.5°C20.5°C596.711.612 h
November 25.7°C16.1°C16.1°C355.310.911 h
December, selected 22.5°C12.9°C12.9°C305.110.511 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 Mission

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 Mission) is explained once on the Mission year overview and on the Sources, method and limits page.

McAllen and Edinburg lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.