Mountain View climate

Mountain View Frost Dates and Growing Season

NOAA 1991-2020 normals for Mtn View, 3.2 km from Mountain View, elevation 716 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mtn View. 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 April 2 and the first fall freeze around October 31, a growing season of about 211 days.

Median at 36°F
last April 14, first October 21
Median at 32°F
last April 2, first October 31
Median at 28°F
last March 19, first November 11

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°FMay 2Apr 27Apr 22Apr 18Apr 14Apr 11Apr 6Apr 2Mar 28
32°FApr 20Apr 13Apr 9Apr 5Apr 2Mar 29Mar 25Mar 19Mar 12
28°FApr 7Apr 1Mar 27Mar 23Mar 19Mar 14Mar 9Mar 4Feb 27
24°FMar 26Mar 20Mar 14Mar 9Mar 5Mar 2Feb 28Feb 22Feb 14
20°FMar 14Mar 8Mar 3Feb 28Feb 23Feb 18Feb 13Feb 7Jan 31
16°FMar 5Feb 27Feb 20Feb 14Feb 8Feb 2Jan 29Jan 23Jan 11

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°FOct 5Oct 11Oct 15Oct 18Oct 21Oct 24Oct 26Oct 29Nov 3
32°FOct 15Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 9Nov 15
28°FOct 26Nov 1Nov 4Nov 8Nov 11Nov 15Nov 20Nov 25Dec 1
24°FNov 5Nov 11Nov 16Nov 20Nov 24Nov 29Dec 2Dec 7Dec 15
20°FNov 17Nov 24Nov 30Dec 3Dec 8Dec 13Dec 18Dec 24Jan 1
16°FNov 29Dec 6Dec 13Dec 19Dec 24Dec 30Jan 3Jan 10Jan 21

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°F211202197191186182177172165
32°F236227220216211207201195187
28°F263254247241236231225218210
24°F292282275268262257250243235
20°F322310304297291285278270259
16°F351337330325318311303295284

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
100% of years
16°F or colder
97% 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
3,632
Cooling degree days, base 65°F
1,727
Growing degree days, base 40°F
7,630
Growing degree days, base 45°F
6,148
Growing degree days, base 50°F
4,816
Growing degree days, base 55°F
3,632
Growing degree days, base 60°F
2,600

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January839019
February638139
March4598135
April20638304
May59143550
June3337784
July0474939
August1438902
September26226650
October18755350
November4647115
December751129

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 3.2 km from Mountain View. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00035046 (Mtn View). Public domain.