Climate · Washington

Washington, NJ climate

Washington has chilly winters and pleasant summers, with plenty of rain. A typical July afternoon reaches 83°, a January night drops to 19°, and about 30 inches of snow falls in a normal winter.

NOAA 1991-2020 climate normals Updated once a decade
July high
83°
33rd coolest of 941 New Jersey towns
January low
19°
76th coldest of 941 New Jersey towns
Rain + melted snow
51 in
10th wettest of 941 New Jersey towns
Snow a winter
30 in
95th snowiest of 898 New Jersey towns
A normal year

What a year in Washington feels like

Winter

39° / 21°
Typical high / low · 9 days with an inch or more of snow

Spring

59° / 38°
Typical high / low · Last frost around Apr 30

Summer

81° / 59°
Typical high / low · 14 days reach 90° in a normal year

Fall

63° / 43°
Typical high / low · First frost around Oct 18
Best months to be outsideMayJunJulAugSepOctHighs of 62–84° and lows of 40° or more
Month by month

Washington weather by month

Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.

MonthHighLowRain + meltSnowWet daysSnow on ground30-yr range
January36°19°3.8" 7.4"1111 18° – 35°
February39°21°3.0" 10.3"814 18° – 36°
March48°28°4.1" 5.8"106 32° – 47°
April60°38°4.0" 0.7"100 45° – 53°
May70°48°4.2" 0120 54° – 64°
June78°56°5.0" 0120 63° – 70°
July83°61°5.0" 0110 67° – 76°
August81°60°4.6" 0100 66° – 74°
September74°53°4.7" 090 61° – 68°
October63°42°4.7" 0.3"90 48° – 60°
November51°33°3.7" 0.3"90 37° – 47°
December41°24°4.5" 4.8"105 25° – 43°
Year60°40°51.2"29.6"12037

“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.

Rain & snow

Rain and snow in Washington

Washington gets 51 inches of rain and melted snow a year. July is the wettest month and February the driest. Rain or snow falls on about 120 days a year. Snow covers the ground about 37 days of the year.

51 in
Rain + melted snow a year
More rain than 90% of U.S. towns
30 in
Snow in a normal winter
More snow than 57% of U.S. towns
37 days
With 1"+ of snow on the ground
More than 57% of U.S. towns

Rain + melted snow by month

Inches of water
5.0"

Snowfall by month

Inches of snow
10"
Frost & the growing season

About 168 frost-free days a year

In half of years the last 32° night comes by April 30 and the first one by October 18. That leaves about 168 frost-free days for gardens, shorter than 63% of U.S. towns.

135
nights at or below 32° in a normal year
2
nights below 0° in a normal year
14
days that reach 90° in a normal year

Freezing nights by month

Average nights at or below 32°

90° days by month

Average days at 90° or more
Heating & cooling

Heating and cooling a home in Washington

Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Washington, 90% of that work is heating and 10% is cooling, so the furnace matters far more than the air conditioner.

90%heating
6,050 heating degree daysMore heating than 57% of U.S. towns
650 cooling degree daysLess cooling than 65% of U.S. towns

Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.

Around Washington

Washington and its neighbors

Washington borders 6 towns with climate data. January nights across them vary by 1.7°. Mount Olive has the coldest January nights (19°) and Tewksbury the hottest July afternoons (85°). Washington’s January low is 19° and its July high 83°.

Randolph: January low 19°, July high 83°Mendham: January low 20°, July high 84°Bedminster: January low 21°, July high 86°Roxbury: January low 19°, July high 83°Washington: January low 19°, July high 85°Independence: January low 19°, July high 84°Oxford: January low 19°, July high 84°Liberty: January low 19°, July high 83°Byram: January low 18°, July high 83°Allamuchy: January low 18°, July high 84°Stanhope: January low 18°, July high 82°Netcong: January low 18°, July high 82°Readington: January low 21°, July high 86°Clinton: January low 20°, July high 85°Califon: January low 19°, July high 83°Union: January low 20°, July high 85°Glen Gardner: January low 20°, July high 84°Bethlehem: January low 19°, July high 84°Hampton: January low 19°, July high 84°High Bridge: January low 20°, July high 84°Chester: January low 20°, July high 84°Mansfield: January low 19°, July high 84°Mount Olive: January low 19°, July high 82°Hackettstown: January low 19°, July high 84°Tewksbury: January low 20°, July high 85°Lebanon: January low 19°, July high 83°Washington: January low 19°, July high 83° WashingtonChesterMansfieldMount OliveHackettstownTewksburyLebanon
ColderMilder18° to 21°
Mount Olive18.5° −0.3°
Washington18.8°
Hackettstown18.8° same
Mansfield18.9° +0.1°
Lebanon18.9° +0.1°
Chester19.7° +0.9°
Tewksbury20.2° +1.4°

Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.

Compared with other towns

How Washington compares

Summer heat83° July high
Cooler than 68% of U.S. towns33rd coolest of 941 New Jersey towns
Winter cold19° January low
Colder than 53% of U.S. towns76th coldest of 941 New Jersey towns
Precipitation51" a year
Wetter than 90% of U.S. towns10th wettest of 941 New Jersey towns
Snow30" a winter
Snowier than 57% of U.S. towns95th snowiest of 898 New Jersey towns
Growing season168 frost-free days
Shorter than 63% of U.S. towns57th shortest of 941 New Jersey towns

Compared with every U.S. town and city on TownTapestry, each counted once.

Then and now

Warmer than it used to be

+2.3°1991–2020 average vs. the 20th century (1901–2000)

The last 30 years in Washington averaged 2.3° warmer than the 1900s. The biggest change is in December (+4.0°). The shift is larger than in 99% of U.S. towns.

❄️ Winter+3.4° now 30°, was 27°
🌷 Spring+2.0° now 49°, was 47°
☀️ Summer+1.9° now 70°, was 68°
🍂 Fall+2.0° now 53°, was 51°

Change by month1991–2020 average minus 1901–2000 average, at Washington’s spot on NOAA’s grid

Year to year

How much a month can swing

A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 18° to 36°. June is the most reliable, staying within 7°.

Coldest to warmest month in 30 yearsNormal
Questions

Common questions about Washington’s climate

What is the coldest month in Washington?

January, with a typical high of 36° and a low of 19°.

What is the hottest month in Washington?

July, with a typical high of 83° and a low of 61°. About 14 days a year reach 90°.

How much snow does Washington get?

About 30 inches in a normal winter, most of it in February.

When is the first frost in Washington?

In half of years the first 32° night comes by October 18, and the last spring frost by April 30.

What is the rainiest month in Washington?

July, with 5.0 inches of rain and melted snow. The year totals 51 inches.

Temperatures and rainfall come from NOAA’s gridded climate normals for Washington itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Pottersville 2 Nnw, NJ (5 mi, snow) and Belvidere Brg, NJ (15 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.

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