Chevy Chase Section Three climate

Chevy Chase Section Three Frost Dates and Growing Season

NOAA 1991-2020 normals for Dalecarlia Rsvr, 5.6 km from Chevy Chase Section Three, elevation 150 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dalecarlia Rsvr. 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 April 9 and the first fall freeze around October 31, a growing season of about 202 days.

Median at 36°F
last April 23, first October 20
Median at 32°F
last April 9, first October 31
Median at 28°F
last March 30, first November 9

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 10May 5Apr 30Apr 27Apr 23Apr 20Apr 17Apr 13Apr 8
32°FApr 26Apr 20Apr 16Apr 12Apr 9Apr 6Apr 3Mar 31Mar 27
28°FApr 12Apr 6Apr 3Apr 1Mar 30Mar 27Mar 22Mar 17Mar 12
24°FApr 2Mar 29Mar 25Mar 21Mar 18Mar 14Mar 11Mar 6Feb 27
20°FMar 26Mar 20Mar 15Mar 10Mar 6Mar 3Feb 28Feb 23Feb 13
16°FMar 14Mar 8Mar 3Feb 28Feb 23Feb 16Feb 8Feb 2Jan 25

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 7Oct 12Oct 15Oct 17Oct 20Oct 23Oct 26Oct 29Nov 2
32°FOct 16Oct 22Oct 25Oct 29Oct 31Nov 2Nov 4Nov 7Nov 13
28°FOct 29Nov 1Nov 4Nov 6Nov 9Nov 12Nov 16Nov 20Nov 27
24°FNov 5Nov 11Nov 15Nov 18Nov 22Nov 26Dec 1Dec 5Dec 13
20°FNov 15Nov 22Nov 29Dec 2Dec 6Dec 12Dec 17Dec 24Jan 1
16°FDec 1Dec 7Dec 15Dec 22Dec 27Dec 31Jan 4Jan 12Jan 21

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°F198192187183179174170164157
32°F223216211206202198194189181
28°F248241236231226222217212206
24°F280270263257251245240234226
20°F308298292284278271265258247
16°F336326317311305301294287274

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
99% 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
4,506
Cooling degree days, base 65°F
1,338
Growing degree days, base 40°F
6,569
Growing degree days, base 45°F
5,224
Growing degree days, base 50°F
4,035
Growing degree days, base 55°F
2,990
Growing degree days, base 60°F
2,091

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January95508
February788010
March649253
April30523213
May10797458
June13265702
July0406871
August2351814
September38166579
October26226255
November559159
December829014

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 5.6 km from Chevy Chase Section Three. 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 USC00182325 (Dalecarlia Rsvr). Public domain.