Ryegate climate

Ryegate Frost Dates and Growing Season

NOAA 1991-2020 normals for Ryegate, 0.3 km from Ryegate, elevation 3650 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ryegate. 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 17 and the first fall freeze around September 23, a growing season of about 127 days.

Median at 36°F
last May 30, first September 12
Median at 32°F
last May 17, first September 23
Median at 28°F
last May 5, first October 3

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 8Jun 4Jun 1May 30May 27May 24May 21May 17
32°FMay 30May 25May 22May 19May 17May 14May 11May 8May 3
28°FMay 19May 14May 11May 8May 5May 2Apr 30Apr 27Apr 22
24°FMay 9May 5May 1Apr 29Apr 26Apr 22Apr 18Apr 14Apr 6
20°FApr 29Apr 23Apr 19Apr 16Apr 12Apr 8Apr 4Apr 1Mar 24
16°FApr 19Apr 13Apr 9Apr 5Apr 1Mar 29Mar 24Mar 18Mar 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°FAug 29Sep 3Sep 6Sep 10Sep 12Sep 14Sep 17Sep 21Sep 26
32°FSep 10Sep 14Sep 17Sep 20Sep 23Sep 26Sep 30Oct 2Oct 6
28°FSep 19Sep 24Sep 27Oct 1Oct 3Oct 5Oct 8Oct 12Oct 16
24°FSep 30Oct 3Oct 6Oct 10Oct 13Oct 16Oct 20Oct 23Oct 27
20°FOct 7Oct 13Oct 18Oct 21Oct 24Oct 26Oct 29Nov 2Nov 6
16°FOct 13Oct 21Oct 25Oct 29Nov 1Nov 3Nov 6Nov 10Nov 16

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°F123116112108104100969183
32°F148141136132127124120115108
28°F168161157153149145140136129
24°F191184178173169165161155149
20°F214206200196192189184179171
16°F237229222216211208202196188

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
7,174
Cooling degree days, base 65°F
369
Growing degree days, base 40°F
4,062
Growing degree days, base 45°F
2,990
Growing degree days, base 50°F
2,102
Growing degree days, base 55°F
1,370
Growing degree days, base 60°F
789

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20100
February1,02301
March86508
April609034
May3676160
June12840366
July18160607
August37138566
September20924284
October577271
November92906
December1,21200

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 0.3 km from Ryegate. 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 USC00247261 (Ryegate). Public domain.