30-year climate normals

Washington County Climate and Weather Averages

Hottest month — July

87.3°

average daily high. The coldest month is January, averaging a low of 25.3°F.

Washington County gets 35.6" of precipitation a year, and 29% of it falls in Apr, May, Jun.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	40.5°	25.3°	2.46"
February	43.6°	27.3°	1.97"
March	52.8°	34.0°	3.04"
April	64.9°	44.3°	3.33"
May	74.4°	54.5°	3.55"
June	82.6°	63.7°	3.36"
July	87.3°	67.9°	2.94"
August	84.9°	65.7°	2.90"
September	77.8°	58.9°	3.83"
October	66.0°	47.4°	2.76"
November	54.4°	37.4°	2.63"
December	44.0°	29.8°	2.83"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 29% falling in the wettest three months (Apr, May, Jun).

January 2.46"

February 1.97"

March 3.04"

April 3.33"

May 3.55"

June 3.36"

July 2.94"

August 2.90"

September 3.83"

October 2.76"

November 2.63"

December 2.83"

Annual total 35.6"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 1,248

Heating degree days How much heating the climate demands 4,716

Approximate annual cooling cost At 21.77¢/kWh, Maryland average $272

Approximate annual electric heating cost Lower where heating is gas rather than electric $359

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Washington County, where electricity is one line of eight.

Common questions

What is the weather like in Washington County?

Washington County averages a high of 87.3°F in July and a low of 25.3°F in January. Annual precipitation is 35.6 inches, with essentially no snow.

When is the rainy season in Washington County?

The wettest stretch is Apr, May, Jun, which accounts for 29% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Washington County?

The average daily high in July, the hottest month, is 87.3°F. That drives 1,248 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Washington County?

Effectively no. Measurable snowfall is rare in Washington County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station HAGERSTOWN WASHINGTON CO AP, MD US (USW00093706), 8.5 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, Maryland residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.