Photo: Jordan W. · CC BY-SA 3.0Fontana reaches 100° on about 19 days a year, more than 95% of U.S. towns
A typical July afternoon reaches 94°, a January night drops to 43°, and snow is almost unheard of.
A year in Fontana at a glance
Each month’s typical high and low, and what it brings.
What stands out about Fontana’s climate
Compared with towns across the U.S., with Fontana’s place in California beside it.
What a year in Fontana feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 19 days a year reach 100°
And 93 days reach 90°. Frost and day counts come from NOAA’s station at Ontario International Airport, 9 miles from the city’s center point, 330 ft lower.
The 2023 USDA map puts Fontana’s center in zone 10a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 32°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 17 inches of rain a year
February is the wettest month and July the driest. Rain falls on about 38 days a year. Snow is rare: about 0.0" in a normal year at Riverside Citrus Exp, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Fontana
40% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55° run from December.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Ontario International Airport.
Living with Fontana’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10a. Frost comes about 1 winter in 2, so the growing year is set by heat, not cold: 19 days at 100° make midsummer the hard season for gardens.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, May, October, November and December. 37 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Fontana from natural hazards, earthquakes are the largest share (51%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Fontana and its neighbors
Every town next door is within a degree of Fontana in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Fontana’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Fontana, CA | 43° | 94° | 17" | 0.0" |
| Corona de Tucson, AZ | 36° | 96° | 14" | 0.1" |
| Del Rio, TX | 40° | 98° | 19" | 0.2" |
| Medford, OR | 32° | 92° | 19" | 3.4" |
| Santa Teresa, NM | 33° | 95° | 9" | 2.0" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Fontana averaged 2.4° warmer than the 1900s. The biggest change is in January (+3.2°).
A bigger shift than in 98% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods. In a city of 221,000 people, part of the change is the city itself: pavement and buildings hold heat (the urban heat island).
How Fontana compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Fontana’s place among California’s.
Fontana weather by month
Highs, lows and precipitation from NOAA’s grid at Fontana’s center; snow, wet days and snow on the ground from Riverside Citrus Exp, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 67° | 43° | 3.9" | 0.0" | 7 | 0 | 51° – 61° |
| February | 68° | 44° | 4.3" | 0.0" | 7 | 0 | 49° – 66° |
| March | 71° | 46° | 2.7" | 0.0" | 6 | 0 | 52° – 66° |
| April | 76° | 49° | 1.0" | 0.0" | 4 | 0 | 57° – 66° |
| May | 80° | 53° | 0.4" | 0.0" | 2 | 0 | 60° – 73° |
| June | 87° | 58° | 0.1" | 0.0" | 1 | 0 | 67° – 78° |
| July | 94° | 62° | 0.0" | 0.0" | 1 | 0 | 73° – 84° |
| August | 95° | 64° | 0.0" | 0.0" | 0 | 0 | 77° – 83° |
| September | 92° | 61° | 0.2" | 0.0" | 1 | 0 | 72° – 81° |
| October | 83° | 54° | 0.7" | 0.0" | 2 | 0 | 64° – 74° |
| November | 74° | 47° | 1.3" | 0.0" | 3 | 0 | 53° – 66° |
| December | 66° | 42° | 2.9" | 0.0" | 5 | 0 | 50° – 60° |
| Year | 79° | 52° | 17.4" | 0.0" | 38 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 49° to 66°. August is the most reliable, staying within 7°.
Where Fontana’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Fontana’s center.
- Snow: Riverside Citrus Exp, CA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Ontario International Airport, 9 miles from the city’s center point, 330 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Fontana’s climate
What is the weather like in Fontana?
A typical July afternoon reaches 94°, a January night drops to 43°, and snow is almost unheard of. Milder January nights than 92% of U.S. towns; hotter July afternoons than 93% of U.S. towns.
How cold does it get in Fontana in winter?
December nights average 42°. About 2 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 50°.
How much snow does Fontana get?
About 0.0 inches in a normal winter at Riverside Citrus Exp, CA, so most winters see none.
How hot does it get in Fontana?
July, with a typical high of 94° and a low of 62°. About 93 days a year reach 90° and 19 reach 100° (Ontario International Airport).
When is the first and last frost in Fontana?
Most years have no frost at all: a 32° night comes in about 41% of winters at Ontario International Airport, usually in December or January.
What growing zone is Fontana in?
Zone 10a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 32°.
What is the best time of year to visit Fontana?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Fontana getting warmer?
Yes: 1991–2020 averaged 2.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 98% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Fontana.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.