ZIP 92509 Zone 10a

California · USDA zone 10a, average annual extreme minimum 30°F to 35°F.

Nearest qualified station: RIVERSIDE MUNI AP, CA US (USW00003171), 3.6 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is January 9. Median first 32°F is December 30. The 50% growing-season length is 362 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

ProbabilityDateHow to read it
90%December 16Earlier date. A last 32°F on or after this day is common.
50%January 9Median.
10%February 21Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

ProbabilityDateHow to read it
10%December 5Earlier date. A first 32°F on or before this day is uncommon.
50%December 30Median.
90%February 6Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this longDays
10%365
50%362
90%319

36°F threshold

10%50%90%
Last, on or afterMarch 13February 13January 2
First, on or beforeNovember 23December 12January 9
Season at least346 days305 days264 days

Station RIVERSIDE MUNI AP, CA US (USW00003171). Completeness flag R, 21 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 57.5%. Freeze dates are conditional on that threshold occurring. Elevation 245.4 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Methodology · California cities