Washington, Pennsylvania climate: Normal weather by month, frost dates and records
Washington's normal year runs from 20°F January nights to 83°F July afternoons, with 41.3 inches of precipitation and 32 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.8°C, January lows of −7°C, July highs of 29°C, 1,050 mm of precipitation a year.
- NOAA stationWashington (3 mi NE)
- Station IDUSC00369318
- Location40.18°N 80.19°W
- Elevation1,300 ft (396 m)
- From the center3 miles
- Population13,334
On October 23, the normal high in Washington is 62°F and the normal low 40°F, and the chance of measurable rain or snow is 38%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Washington.
- Jan 37° 20°
- Feb 40° 22°
- Mar 49° 29°
- Apr 63° 40°
- May 72° 49°
- Jun 80° 58°
- Jul 83° 62°
- Aug 83° 60°
- Sep 76° 54°
- Oct 64° 43°
- Nov 52° 33°
- Dec 41° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Washington each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 20°F. The most precipitation falls in June (4.48 in), the least in February (2.52 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 37°F | 20°F | 28.4°F | 3.32 | 9.9 | 16 | <1 | 27 | 9 h 40 min |
| February | 40°F | 22°F | 30.9°F | 2.52 | 7.5 | 13 | <1 | 24 | 10 h 40 min |
| March | 49°F | 29°F | 39.1°F | 3.51 | 6.1 | 13 | <1 | 20 | 11 h 50 min |
| April | 63°F | 40°F | 51.1°F | 3.26 | 0.6 | 14 | <1 | 7 | 13 h 10 min |
| May | 72°F | 49°F | 60.5°F | 4.14 | 0.0 | 14 | <1 | 1 | 14 h 20 min |
| June | 80°F | 58°F | 68.9°F | 4.48 | 0.0 | 13 | 1 | <1 | 15 h |
| July | 83°F | 62°F | 72.6°F | 3.63 | 0.0 | 12 | 3 | <1 | 14 h 50 min |
| August | 83°F | 60°F | 71.4°F | 3.48 | 0.0 | 10 | 2 | <1 | 13 h 50 min |
| September | 76°F | 54°F | 64.8°F | 3.57 | 0.0 | 10 | 1 | <1 | 12 h 30 min |
| October | 64°F | 43°F | 53.4°F | 3.00 | 0.0 | 11 | <1 | 4 | 11 h 10 min |
| November | 52°F | 33°F | 42.7°F | 3.11 | 1.8 | 12 | <1 | 15 | 10 h |
| December | 41°F | 26°F | 33.7°F | 3.32 | 6.0 | 15 | <1 | 25 | 9 h 20 min |
| Year (annual) | 62°F | 41°F | 51.4°F | 41.34 | 31.9 | 154 | 6 | 122 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −7°C | −2.0°C | 84 mm | 25 cm |
| February | 5°C | −6°C | −0.6°C | 64 mm | 19 cm |
| March | 10°C | −2°C | 3.9°C | 89 mm | 15 cm |
| April | 17°C | 4°C | 10.6°C | 83 mm | 2 cm |
| May | 22°C | 10°C | 15.8°C | 105 mm | 0 cm |
| June | 27°C | 14°C | 20.5°C | 114 mm | 0 cm |
| July | 29°C | 17°C | 22.6°C | 92 mm | 0 cm |
| August | 28°C | 16°C | 21.9°C | 88 mm | 0 cm |
| September | 24°C | 12°C | 18.2°C | 91 mm | 0 cm |
| October | 18°C | 6°C | 11.9°C | 76 mm | 0 cm |
| November | 11°C | 1°C | 5.9°C | 79 mm | 5 cm |
| December | 5°C | −3°C | 0.9°C | 84 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00369318; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Washington?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (10).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00369318.
When is the last frost in Washington?
In Washington, the last spring frost (32°F) comes after April 24 in half of years and after May 18 in one year in ten; the first autumn frost comes before October 23 in half of years and before October 8 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 241 year in 10 after May 18; 9 in 10 after April 8
- First autumn frost, half of years before
- October 231 year in 10 before October 8; 9 in 10 before November 5
NOAA puts the median frost-free season at 181 days, and the season without a hard freeze (28°F) at 206 days.
A hard freeze (28°F) comes after April 11 in half of springs and before November 2 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Washington in zone 6b in ZIP code 15301, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Washington's NOAA station is in zone 6b: the coldest night of a typical year reaches −1°F (22 complete years).
Frost dates for every NOAA station in Pennsylvania · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00369318; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Washington?
In a normal year in Washington, 6 days a year reach 90°F, 122 nights fall to 32°F or colder and 154 days bring measurable precipitation.
- Days at 90°F or more
- 6a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 122a normal year
- Days that stay below freezing
- 38high of 32°F or less
- Days with 0.01 inch of precipitation
- 154a normal year
- Days with 1 inch of snow or more
- 10a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00369318.
How sunny is Washington?
Over a year 69% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Washington, 3.8 kWh per square metre a day. August is the sunniest month (78%) and December the cloudiest (52%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 53% | 1.6 |
| February | 59% | 2.4 |
| March | 61% | 3.4 |
| April | 67% | 4.6 |
| May | 70% | 5.4 |
| June | 74% | 5.9 |
| July | 77% | 5.9 |
| August | 78% | 5.3 |
| September | 76% | 4.3 |
| October | 67% | 2.9 |
| November | 65% | 2.0 |
| December | 52% | 1.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Washington need?
A normal year in Washington brings 5,674 heating degree days, 6% more than the median U.S. place (5,373), and 762 cooling degree days, 16% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,122 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,134 | 0 |
| February | 955 | 0 |
| March | 806 | 1 |
| April | 431 | 12 |
| May | 193 | 53 |
| June | 39 | 154 |
| July | 5 | 239 |
| August | 8 | 206 |
| September | 90 | 84 |
| October | 371 | 12 |
| November | 671 | 1 |
| December | 972 | 0 |
| Year (annual) | 5,674 | 762 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00369318. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Washington's climate compare?
Washington is warmer than 65 of the other 107 places with their own NOAA record in Pennsylvania, and wetter than 17. Across the 7,247 U.S. stations with normals, its annual mean of 51.4°F is warmer than 47%.
In the Köppen classification computed from these normals, Washington is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Washington share this climate record?
21 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Canonsburg, PA9,601 people · 6 mi N
- McMurray, PA4,348 people · 9 mi NE
- McGovern, PA4,290 people · 4 mi NW
- Thompsonville, PA3,767 people · 8 mi NE
- Southpointe, PA3,277 people · 8 mi N
- Wolfdale, PA3,150 people · 6 mi W
- Cecil-Bishop, PA2,752 people · 10 mi N
- Muse, PA2,687 people · 8 mi N
- East Washington, PA1,821 people · 2 mi W
- Houston, PA1,151 people · 5 mi N
- Lawrence, PA1,055 people · 9 mi NE
- Laboratory, PA993 people · 2 mi SW
- Eighty Four, PA795 people · 3 mi E
- Wylandville, PA662 people · 4 mi NE
- Cokeburg, PA609 people · 9 mi SE
- Strabane, PA569 people · 5 mi N
- Meadowlands, PA416 people · 3 mi NW
- Midland, PA301 people · 6 mi N
- Hendersonville, PA157 people · 9 mi N
- Westland, PA36 people · 8 mi NW
- Green Hills, PA19 people · 8 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Washington's climate
What is the coldest month in Washington?
January, with a normal high of 37°F and a normal low of 20°F. The warmest is July (83°F by day, 62°F at night).
Does it snow in Washington?
Yes: 32 inches in a normal year, falling on 27 days with 0.1 inch or more, the most in January (9.9 inches).
What is the rainiest month in Washington?
June, with 4.48 in of precipitation in a normal year; the driest is February with 2.52 in.
What plant hardiness zone is Washington in?
The USDA's 2023 map puts Washington in zone 6b in ZIP code 15301, the nearest ZIP area. By the same method at Washington's NOAA station, the coldest night of a typical year reaches −1°F (22 years, 1991-2020): zone 6b.
How late can frost come in Washington?
In half of years the last 32°F night comes after April 24; in one year in ten it comes after May 18. Waiting until May 18 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Washington in OctoberThis month day by day, its records and recent years
- Pennsylvania climateThe statewide normals and every place in the state
- Charleroi, PA16 miles from this station, 52.9°F a year
- Donora, PA17 miles from this station, 52.1°F a year
- West Mifflin, PA19 miles from this station, 52.4°F a year
- Waynesburg, PA19 miles from this station, 51.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made