Climateby Month

Fontana, CA climate by month

NOAA 1991-2020 normals · 1,236 ft elevation

Summers in Fontana are hot; winters are mild. Highs peak at 95°F in August and fall to 67°F in December. The wettest month is February (about 8 wet days) and the driest is August (about 1). Snow is rare. The most comfortable time to visit is March, April and May.

Warmest month
95°F
August normal high
Coldest month
44°F
December normal low
Wet days a year
43
12.9 in of precipitation
Muggy days a year
2
dew point 65°F or higher

How warm is Fontana?

Normal highs range from 67°F in December to 95°F in August.

40°60°80°100° January: normal high 68°F (20°C), low 45°F (7°C) February: normal high 68°F (20°C), low 46°F (8°C) March: normal high 72°F (22°C), low 49°F (9°C) April: normal high 76°F (24°C), low 51°F (11°C) May: normal high 80°F (27°C), low 56°F (13°C) June: normal high 86°F (30°C), low 60°F (16°C) July: normal high 94°F (34°C), low 65°F (18°C) August: normal high 95°F (35°C), low 65°F (18°C) 95° 65° September: normal high 91°F (33°C), low 64°F (18°C) October: normal high 83°F (28°C), low 57°F (14°C) November: normal high 75°F (24°C), low 49°F (9°C) December: normal high 67°F (19°C), low 44°F (7°C) 67° 44° JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Fontana?

February has the most wet days (about 8); the year brings about 13 in of precipitation.

January: 7 wet days February: 8 wet days 8 March: 6 wet days April: 4 wet days May: 3 wet days June: 1 wet days July: 1 wet days August: 1 wet days 1 September: 1 wet days October: 3 wet days November: 4 wet days December: 6 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How humid is Fontana?

Muggy days peak in July, at about 1 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 0 muggy days July: 1 muggy days 1 August: 0 muggy days September: 1 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at March Air Reserve Base, 17 mi SE of the city center (the nearest airport with complete hourly records).

How much daylight?

Daylight ranges from about 9.9 hours in December to 14.4 hours in June.

January: 10.2 hours of daylight February: 11.0 hours of daylight March: 12.0 hours of daylight April: 13.1 hours of daylight May: 13.9 hours of daylight June: 14.4 hours of daylight 14.4 July: 14.2 hours of daylight August: 13.4 hours of daylight September: 12.4 hours of daylight October: 11.3 hours of daylight November: 10.4 hours of daylight December: 9.9 hours of daylight 9.9 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Fontana, 1991-2020
MonthHighLowPrecip.Wet daysMuggy daysDaylight
January 68°F45°F 2.8 in7 0 10.2 h
February 68°F46°F 3.0 in8 0 11.0 h
March 72°F49°F 2.0 in6 0 12.0 h
April 76°F51°F 0.9 in4 0 13.1 h
May 80°F56°F 0.3 in3 0 13.9 h
June 86°F60°F 0.1 in1 0 14.4 h
July 94°F65°F 0.1 in1 1 14.2 h
August 95°F65°F 0.09 in1 0 13.4 h
September 91°F64°F 0.1 in1 1 12.4 h
October 83°F57°F 0.5 in3 0 11.3 h
November 75°F49°F 0.9 in4 0 10.4 h
December 67°F44°F 2.0 in6 0 9.9 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Fontana

By our comfort score, the best months are March, April and May.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 651650
Feb 631350
Mar 711741
Apr 731623
May 741615
Jun 607011
Jul 441123
Aug 410024
Sep 474018
Oct 601218
Nov 701822
Dec 641540

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Fontana

The last spring frost typically comes around Jan 9, and the first fall frost around Dec 30, leaving 362 frost-free days in a typical year.

Frost and freeze dates for Fontana
Typical date1 year in 10
Last spring frost (32°F)Jan 9after Feb 21
First fall frost (32°F)Dec 30before Dec 5
Hard freeze (28°F)in about 7% of years; no typical date
Frost-free season362 daysunder 319 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Riverside Muni Airport (USW00003171), NOAA 1991-2020 freeze probabilities. Frost dates for every city in California.

Hottest and coldest readings, 1991-2020

The highest reading was 118°F (September 5, 2020); the lowest was 25°F (January 14, 2007).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Fontana

Similar climates elsewhere

Where the numbers come from

  • Temperature: Ontario Intl Airport (USW00003102), 9.8 mi WSW of the city center, 949 ft (287 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Rain: Redlands (USC00047306), 14 mi ESE of the city center, 1,410 ft (174 ft higher than the city). NOAA normals and daily records, 1991-2020.
  • Snowfall and snow depth: Riverside Citrus Exp (USC00047473), 9.6 mi SSE of the city center, 986 ft (250 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Frost dates: Riverside Muni Airport (USW00003171), 9.7 mi S of the city center, 805 ft (431 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Humidity and wind by hour and cloud cover: March AFB (USW00023119), 17 mi SE of the city center, 1,516 ft (280 ft higher than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: March Air Reserve Base (722860-23119), 17 mi SE of the city center, 1,536 ft (300 ft higher than the city). Hourly observations, 1991-2020.

Distances from the city center (USGS). Methodology · Report an error