What is the highest temperature ever recorded in Ontario, CA?

The record high temperature in Ontario, CA is 121°F, recorded on September 6, 2020.

What is the lowest temperature ever recorded in Ontario, CA?

The record low temperature in Ontario, CA is 20°F, recorded on January 14, 2007.

Historical Weather in Ontario, CA

Name: Ontario, CA Temperature Records
Creator: NOAA

See 55+ years of weather history for any date in Ontario going back to 1970.

Part of California weather history · California temperature records

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Monthly Climate Averages

Historical temperature and precipitation averages for Ontario, CA, based on 55+ years of weather data.

Warmest MonthAugustAvg High: 94°F / Low: 63°F

Coldest MonthDecemberAvg High: 67°F / Low: 41°F

Jan

67°/ 42°

💧 11.5"

Feb

68°/ 43°

💧 12.5"

Mar

71°/ 46°

💧 8.4"

Apr

75°/ 48°

💧 4.9"

May

79°/ 53°

💧 4.5"

Jun

86°/ 58°

💧 1.5"

Jul

93°/ 62°

💧 3.2"

Aug

94°/ 63°

💧 8.4"

Sep

91°/ 61°

💧 4.3"

Oct

82°/ 54°

💧 5.5"

Nov

74°/ 46°

💧 6.2"

Dec

67°/ 41°

💧 9.5"

Temperatures in Fahrenheit. Precipitation and snowfall in inches.

Ontario, CA Temperature Range by Month

Average monthly highs and lows. The shaded band shows the typical daily temperature range.

Avg high Avg low

Ontario, CA Monthly Precipitation

Average rainfall per month, in inches.

Rain (in)

Ontario, CA Daily Temperature Calendar

Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.

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Hotter

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Best Time to Visit Ontario, CA

Ontario, CA has no months that meet our "pleasant" threshold — every season has tradeoffs.

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Pleasant (65-82°F, ≤2.5" rain) Mild Less ideal

Ontario Temperature Records

Record High: The hottest temperature ever recorded in Ontario, CA is 121°F, set on September 6, 2020.
Record Low: The coldest temperature ever recorded in Ontario, CA is 20°F, set on January 14, 2007.
Data Coverage: Based on 29 years of data from NOAA weather station: ONTARIO INTL AP.

All-Time Record High

121°F

September 6, 2020

All-Time Record Low

20°F

January 14, 2007

Monthly Temperature Records in Ontario

Month	Record High	Record Low
January	101°F(2003)	20°F(2007)
February	95°F(2016)	23°F(2013)
March	97°F(2011)	28°F(2002)
April	106°F(2004)	30°F(2013)
May	105°F(2003)	37°F(2017)
June	115°F(2016)	42°F(1999)
July	120°F(2018)	47°F(2013)
August	115°F(2017)	48°F(2013)
September	121°F(2020)	39°F(2013)
October	111°F(2020)	33°F(2009)
November	100°F(2010)	27°F(2004)
December	92°F(2021)	21°F(2011)