Climate averages 1991–2020

Fontana weather
in July.

A hot, very dry month: the 2nd warmest and the 2nd driest of the year.

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

Average high 32.4°C Daytime mean, July
Average low 18.7°C Night-time mean, July
Rainfall 2.2 mm fewer than one day with ≥1 mm
Daylight 14 h Sunrise to sunset, per day
Every month in Fontana · average highYear overview

July is a hot month in Fontana: daytime highs average 32.4°C and nights cool to about 18.7°C. By daytime temperature it is the 2nd warmest of the 12 months.

Expect about 2.2 mm of rain on fewer than one day, which makes July a very dry month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 11 min on an average July day.

The nearest other city in this atlas is San Bernardino (13 km away). In July its highs average 32.9°C, about as warm as Fontana, with 12 mm of rain.

Among the 498 cities listed in the United States, Fontana ranks joint 117th of 498 for the warmest July highs and joint 71st of 498 for the driest July (rainfall, lowest first). The mean July high of those 498 cities is 30.3°C; Fontana is 2.2°C warmer than that mean.

From July to August, average highs rise by 1.0°C to 33.5°C, and monthly rainfall falls from 2.2 mm to 1.1 mm.

The annual picture

July 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. 0510152025303540 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 1500

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

Every month, side by side

Fontana climate table

1991–2020
Monthly climate averages for Fontana, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 16.7°C4.3°C4.3°C966.610.210 h
February 17.1°C5.2°C5.2°C1117.410.911 h
March 19.3°C6.9°C6.9°C686.812.012 h
April 21.9°C8.8°C8.8°C324.613.013 h
May 24.8°C11.7°C11.7°C152.613.914 h
June 29.0°C15.0°C15.0°C3.40.514.414 h
July, selected 32.4°C18.7°C18.7°C2.20.514.214 h
August 33.5°C19.3°C19.3°C1.10.313.413 h
September 31.6°C17.0°C17.0°C5.51.212.412 h
October 26.3°C12.2°C12.2°C223.111.411 h
November 20.9°C7.5°C7.5°C303.510.410 h
December 16.3°C4.1°C4.1°C675.89.910 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

July in nearby cities

Distance from Fontana

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

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