Mariposa County climate

Mariposa County Frost Dates and Growing Season

NOAA 1991-2020 normals for Yosemite Village 12 W, 21.1 km from Mariposa County, elevation 6620 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Yosemite Village 12 W. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around May 12 and the first fall freeze around November 1, a growing season of about 171 days.

Median at 36°F
last May 24, first October 18
Median at 32°F
last May 12, first November 1
Median at 28°F
last April 26, first November 13

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FJun 14Jun 6Jun 2May 30May 24May 20May 15May 11May 3
32°FJun 4May 28May 22May 17May 12May 6Apr 30Apr 25Apr 18
28°FMay 23May 14May 7Apr 30Apr 26Apr 19Apr 13Apr 8Mar 31
24°FMay 4Apr 24Apr 14Apr 9Apr 4Mar 31Mar 22Mar 13Mar 1
20°FApr 12Apr 3Mar 25Mar 18Mar 11Mar 4Feb 26Feb 14Jan 28
16°FMar 28Mar 15Mar 3Feb 25Feb 14Feb 1Jan 21Jan 10Dec 30

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 27Oct 3Oct 9Oct 14Oct 18Oct 23Oct 28Nov 2Nov 9
32°FOct 5Oct 13Oct 21Oct 28Nov 1Nov 5Nov 10Nov 16Nov 23
28°FOct 18Oct 28Nov 2Nov 8Nov 13Nov 19Nov 25Dec 1Dec 7
24°FNov 3Nov 12Nov 20Nov 27Dec 1Dec 6Dec 10Dec 15Dec 25
20°FNov 20Dec 1Dec 6Dec 12Dec 18Dec 25Jan 1Jan 9Jan 24
16°FDec 4Dec 14Dec 22Dec 30Jan 4Jan 12Jan 22Feb 1Feb 23

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F176165157151146140134127118
32°F205193184177171164157148135
28°F238224217208201193186177163
24°F278263254245236229220211196
20°F325306296285276267258247233
16°F365364349334320308299284269

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
98% of years
16°F or colder
82% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
5,919
Cooling degree days, base 65°F
308
Growing degree days, base 40°F
4,347
Growing degree days, base 45°F
3,142
Growing degree days, base 50°F
2,151
Growing degree days, base 55°F
1,366
Growing degree days, base 60°F
749

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January84407
February80805
March82807
April685031
May4647126
June19934307
July34109541
August3395527
September13752380
October38010166
November652045
December855010

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 21.1 km from Mariposa County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00053150 (Yosemite Village 12 W). Public domain.