Maeser climate

Maeser Frost Dates and Growing Season

NOAA 1991-2020 normals for Vernal, 6 km from Maeser, elevation 5345 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Vernal. 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 7 and the first fall freeze around October 6, a growing season of about 150 days.

Median at 36°F
last May 23, first September 27
Median at 32°F
last May 7, first October 6
Median at 28°F
last April 25, first October 18

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 9Jun 4May 31May 27May 23May 20May 15May 11May 5
32°FMay 28May 20May 15May 10May 7May 3May 1Apr 28Apr 24
28°FMay 11May 4May 1Apr 28Apr 25Apr 22Apr 19Apr 16Apr 11
24°FApr 28Apr 23Apr 19Apr 16Apr 13Apr 9Apr 6Apr 1Mar 25
20°FApr 16Apr 8Apr 4Mar 31Mar 27Mar 21Mar 16Mar 11Mar 6
16°FMar 31Mar 24Mar 15Mar 11Mar 8Mar 6Mar 3Feb 28Feb 20

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 13Sep 18Sep 21Sep 24Sep 27Sep 29Oct 1Oct 4Oct 8
32°FSep 23Sep 27Sep 30Oct 3Oct 6Oct 8Oct 12Oct 15Oct 20
28°FOct 3Oct 8Oct 12Oct 16Oct 18Oct 21Oct 23Oct 26Oct 30
24°FOct 15Oct 20Oct 22Oct 25Oct 28Oct 30Nov 2Nov 6Nov 11
20°FOct 23Oct 28Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 20
16°FNov 1Nov 5Nov 11Nov 14Nov 17Nov 20Nov 23Nov 26Nov 30

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°F146139134130126122116111103
32°F170163158154150146140134125
28°F193186181178174170165159152
24°F219211206201197193189185177
20°F246238233227222217211206199
16°F270264258253249244238232223

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
100% 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
7,115
Cooling degree days, base 65°F
563
Growing degree days, base 40°F
4,497
Growing degree days, base 45°F
3,434
Growing degree days, base 50°F
2,514
Growing degree days, base 55°F
1,730
Growing degree days, base 60°F
1,078

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,40700
February1,07000
March81206
April549048
May27710227
June6897480
July5243704
August10182637
September14531345
October527067
November91202
December1,33300

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 6 km from Maeser. 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 USC00429111 (Vernal). Public domain.