Riverview climate

Riverview Frost Dates and Growing Season

NOAA 1991-2020 normals for Rock Hill York CO AP, 7.3 km from Riverview, elevation 669 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rock Hill York CO AP. 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 March 31 and the first fall freeze around November 4, a growing season of about 218 days.

Median at 36°F
last April 13, first October 26
Median at 32°F
last March 31, first November 4
Median at 28°F
last March 18, first November 16

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°FApr 28Apr 22Apr 19Apr 16Apr 13Apr 9Apr 6Apr 2Mar 29
32°FApr 15Apr 9Apr 6Apr 2Mar 31Mar 27Mar 23Mar 18Mar 13
28°FApr 4Mar 30Mar 26Mar 22Mar 18Mar 15Mar 11Mar 5Feb 27
24°FMar 26Mar 19Mar 14Mar 9Mar 4Feb 28Feb 24Feb 18Feb 8
20°FMar 14Mar 6Feb 28Feb 23Feb 17Feb 10Feb 4Jan 30Jan 20
16°FMar 3Feb 21Feb 12Feb 4Jan 31Jan 27Jan 19Jan 11Jan 2

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 14Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 3Nov 7
32°FOct 23Oct 27Oct 31Nov 1Nov 4Nov 6Nov 10Nov 13Nov 19
28°FNov 1Nov 6Nov 9Nov 13Nov 16Nov 19Nov 24Nov 29Dec 4
24°FNov 13Nov 18Nov 23Nov 28Dec 1Dec 5Dec 9Dec 19Dec 29
20°FNov 27Dec 3Dec 6Dec 13Dec 21Dec 29Jan 2Jan 7Jan 15
16°FDec 8Dec 19Dec 27Jan 1Jan 5Jan 10Jan 14Jan 21Feb 1

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°F215209204200196193189184178
32°F241233228223218215211205199
28°F269260253248243238233227219
24°F304293285279273266260253245
20°F340328320311305299292283269
16°F365361350342335328319310298

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
99% of years
16°F or colder
84% 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
3,141
Cooling degree days, base 65°F
1,706
Growing degree days, base 40°F
7,895
Growing degree days, base 45°F
6,335
Growing degree days, base 50°F
4,934
Growing degree days, base 55°F
3,692
Growing degree days, base 60°F
2,615

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January724034
February559151
March4028152
April17042333
May40153578
June1343792
July0457922
August0415880
September14235670
October15946360
November4274114
December646148

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 7.3 km from Riverview. 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 USW00053871 (Rock Hill York CO AP). Public domain.