ClimateAverages

Rialto Climate

California, United States of America · population 103,132 · 373 weather stations within 200 km · records 1837 to 2025

Average annual daytime high
24.7°C
Warmest month · July
34.3°C
Typical daytime high
Coldest month · January
3.4°C
Typical overnight low

Rialto has an average annual daytime high of 24.7°C, based on the 1951 to 1980 baseline. Its warmest month is July, when highs typically reach 34.3°C, and its coldest is January, with overnight lows near 3.4°C.

Month by month averages

MonthAvg highAvg low
January16.4°C3.4°CColdest
February18.1°C4.4°C
March19.3°C5.5°C
April22.2°C7.2°C
May25.4°C10.1°C
June29.8°C12.9°C
July34.3°C16.4°CWarmest
August33.9°C16.6°C
September31.9°C14.6°C
October26.9°C10.5°C
November21.2°C6.4°C
December17.4°C3.7°C

Temperature range across the year

1°10°19°28°36°JanFebMarAprMayJunJulAugSepOctNovDec
Daytime high Overnight low
Hottest year on record
2014
+2.1°C vs. 1951–1980
Coldest year on record
1851
-2.2°C vs. 1951–1980

These figures reflect annual averages, not single-day records. Daily observations are outside this dataset's precision.

Is Rialto getting hotter?

Since 1900, Rialto's average temperature has risen by +1.2°C. Compared to the earliest station records that begin in 1837, warming totals +1.7°C.

16.3°16.8°17.4°17.9°18.4°1951–1980 baseline190019251950197520002025

20-year smoothed annual temperature reconstructed from station anomalies. Dashed line: 1951–1980 baseline.

Best time to visit
January to December

Daytime highs sit within a comfortable 15°C to 26°C range.

FAQ

What is the average temperature in Rialto?

Rialto's average annual daytime high is 24.7°C, based on the 1951 to 1980 baseline period. The warmest month is July, with highs averaging 34.3°C, and the coldest is January, with lows averaging 3.4°C.

What is the warmest month in Rialto?

July is the warmest month in Rialto, with typical daytime highs of 34.3°C.

What is the hottest year on record for Rialto?

2014 is the hottest year on record for Rialto, running +2.1°C above the 1951 to 1980 baseline.

Is Rialto getting hotter?

Yes. Since 1900, Rialto has warmed by roughly +1.2°C.

When is the best time to visit Rialto?

January to December typically offers the most comfortable daytime highs, in the 15°C to 26°C range.

Nearby cities

Baseline period 1951 to 1980. Monthly averages are the mean of station observations weighted by proximity. Warming trend is the 20-year smoothed anomaly against that baseline.