Phillips County climate

Phillips County Frost Dates and Growing Season

NOAA 1991-2020 normals for Malta, 11.5 km from Phillips County, elevation 2262 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Malta. 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 10 and the first fall freeze around September 29, a growing season of about 139 days.

Median at 36°F
last May 19, first September 20
Median at 32°F
last May 10, first September 29
Median at 28°F
last April 30, first October 6

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 31May 27May 24May 22May 19May 17May 15May 12May 8
32°FMay 22May 17May 14May 12May 10May 8May 5May 2Apr 29
28°FMay 12May 7May 4May 1Apr 30Apr 27Apr 22Apr 18Apr 13
24°FMay 1Apr 27Apr 23Apr 20Apr 16Apr 12Apr 10Apr 6Apr 1
20°FApr 21Apr 16Apr 12Apr 8Apr 5Apr 2Mar 31Mar 24Mar 17
16°FApr 13Apr 7Apr 3Mar 31Mar 28Mar 24Mar 19Mar 15Mar 10

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 6Sep 12Sep 16Sep 18Sep 20Sep 22Sep 24Sep 27Sep 30
32°FSep 17Sep 21Sep 24Sep 26Sep 29Oct 1Oct 3Oct 6Oct 10
28°FSep 23Sep 28Oct 1Oct 3Oct 6Oct 9Oct 12Oct 15Oct 19
24°FSep 29Oct 4Oct 9Oct 12Oct 15Oct 18Oct 21Oct 25Oct 30
20°FOct 9Oct 14Oct 18Oct 21Oct 25Oct 28Oct 31Nov 3Nov 7
16°FOct 18Oct 24Oct 29Oct 31Nov 2Nov 5Nov 8Nov 12Nov 18

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°F138133129126122119115111105
32°F157151147143139137133129123
28°F181174169165160156152148141
24°F202194190185181176173168160
20°F224215210205200196192186177
16°F240233227222218213208202196

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
7,826
Cooling degree days, base 65°F
553
Growing degree days, base 40°F
4,349
Growing degree days, base 45°F
3,310
Growing degree days, base 50°F
2,412
Growing degree days, base 55°F
1,650
Growing degree days, base 60°F
1,028

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,46900
February1,21800
March99207
April574153
May30513211
June8869432
July12224677
August28203640
September19341316
October582371
November99506
December1,37200

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 11.5 km from Phillips County. 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 USC00245334 (Malta). Public domain.