Frost Dates
Frost Dates · California

Frost dates for Merced, California

California · first & last freeze, from NOAA 1991–2020 climate normals

Typical last spring freeze (32°F)
March 3
median date, 1991–2020
Typical first fall freeze (32°F)
November 24
median date, 1991–2020
Typical frost-free season
266 days
between the median dates

In a typical year, the last spring freeze around Merced comes near March 3 and the first fall freeze near November 24. One year in ten, a freeze still arrives after April 10 in spring — and one year in ten, the first fall freeze has already landed by November 5. NCEI's own growing-season statistic (days between freezes, percentiled per year) puts the median at 263 days.

JFMAMJJASONDMarch 3November 24
The year at a glance: blue bands span the 9-in-10 to 1-in-10 range where the last spring / first fall 32°F freeze lands; the green band is the typical frost-free window between the median dates. Measured at Merced, CA (USC00045532), 2.4 mi from the city's census reference point, elev. 154 ft. NOAA/NCEI 1991–2020 normals.

Freeze-date probabilities, three thresholds

ThresholdLast spring — 9 in 10 years past byLast spring — typical (median)Last spring — 1 in 10 years later thanFirst fall — 1 in 10 years byFirst fall — typical (median)First fall — 9 in 10 years by
36°F — near-freezing (frost can occur)March 6April 7May 1October 21November 8November 24
32°F — freezingFebruary 2March 3April 10November 5November 24December 14
28°F — hard freezeDecember 28February 2March 11November 22December 11January 14

Measured at Merced, CA (USC00045532), 2.4 mi from the city's census reference point, elev. 154 ft. NOAA/NCEI 1991–2020 normals. Read each date column as odds over the 30-year record — e.g. "9 in 10 years past by" means only one spring in ten saw a later freeze than that date.

Frost-free windows (computed)

Window (32°F ends)OpensClosesLength
Cautious (1-in-10 freeze risk at each end)April 10November 5209 days
Typical (median freeze dates)March 3November 24266 days
Gambler's (9-in-10 freeze risk at each end)February 2December 14315 days

Pure arithmetic on the freeze-date percentiles above — the "cautious" window opens on the date only 1 year in 10 still sees a later spring freeze, and closes on the date by which only 1 year in 10 has already frozen.

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