Rose City climate

Rose City Frost Dates and Growing Season

NOAA 1991-2020 normals for Lupton 1S, 7.4 km from Rose City, elevation 908 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lupton 1S. 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 21 and the first fall freeze around September 29, a growing season of about 129 days.

Median at 36°F
last June 3, first September 16
Median at 32°F
last May 21, first September 29
Median at 28°F
last May 7, first October 10

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 23Jun 14Jun 10Jun 6Jun 3Jun 1May 28May 25May 20
32°FJun 5May 31May 27May 24May 21May 19May 15May 10May 5
28°FMay 23May 18May 15May 11May 7May 4Apr 30Apr 28Apr 24
24°FMay 11May 6May 2Apr 29Apr 26Apr 23Apr 20Apr 16Apr 10
20°FApr 28Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 4Mar 31
16°FApr 17Apr 12Apr 8Apr 5Apr 3Apr 1Mar 30Mar 26Mar 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 1Sep 6Sep 11Sep 14Sep 16Sep 20Sep 22Sep 25Sep 30
32°FSep 15Sep 20Sep 23Sep 26Sep 29Oct 1Oct 3Oct 6Oct 11
28°FSep 27Oct 1Oct 4Oct 7Oct 10Oct 13Oct 17Oct 20Oct 26
24°FOct 9Oct 14Oct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 10
20°FOct 24Oct 30Nov 1Nov 4Nov 7Nov 11Nov 14Nov 19Nov 23
16°FNov 2Nov 7Nov 11Nov 15Nov 18Nov 21Nov 25Nov 28Dec 3

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°F12311711310910499938876
32°F150143138133129125121116109
28°F177169164159155151146139132
24°F204197192187182177173167159
20°F229221216212208205200195187
16°F251242237232228224220215209

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
8,031
Cooling degree days, base 65°F
300
Growing degree days, base 40°F
3,763
Growing degree days, base 45°F
2,801
Growing degree days, base 50°F
1,970
Growing degree days, base 55°F
1,265
Growing degree days, base 60°F
695

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,44100
February1,26300
March1,11304
April700132
May36216177
June11561398
July40115539
August5880487
September22525268
October580261
November89705
December1,23700

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 7.4 km from Rose City. 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 USC00204967 (Lupton 1S). Public domain.