Frost dates in Pomona, California

NOAA 1991–2020 normals for a 32 °F freeze. Low spots and the edge of town run colder than downtown.

Short answer

The average last spring frost in Pomona is January 17, and the average first fall frost is December 19, from NOAA's Chino Airport station, 9 miles from the middle of Pomona. 1 year in 10 the last frost comes after February 22, and the first one by November 27. That leaves about 336 frost-free days. Pomona is in USDA planting zone 10a.

Weather stations around Pomona

The first row is the date most people in Pomona go by. The others show how far the dates move across the area.

Station	Last spring frost	First fall frost	Frost-free
Chino Airport 9 mi away, 650 ft	January 17 1 in 10 after February 22	December 19 1 in 10 by November 27	336 days
Pomona/Fairplex 2 mi away, 999 ft	January 8 1 in 10 after February 18	December 28 1 in 10 by December 5	354 days
Ontario Intl Airport 9 mi away, 949 ft	January 4 1 in 10 after February 7	December 30 1 in 10 by December 11	360 days
Anaheim 14 mi away, 235 ft	Frost too rare to date (32 °F in under 1 year in 10)
Fullerton Muni Airport 18 mi away, 96 ft	Frost too rare to date (32 °F in under 1 year in 10)

Distances are from the middle of Pomona as the Census Bureau maps it. The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. The planting zone is the USDA 2023 zone for ZIP code 91766, at the middle of the city.

Your exact ZIP code

Pomona covers a lot of ground. For the station nearest your own street, and its planting zone, type your ZIP code.

How these dates work

Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.

The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.

More frost dates

All of California, station by station.

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