Pasco, Washington climate: Normal weather by month, frost dates and records
Pasco's normal year runs from 27°F December nights to 93°F July afternoons, with 7.6 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.8°C, December lows of −3°C, July highs of 34°C, 194 mm of precipitation a year.
- NOAA stationPasco Tri Cities Airport
- Station IDUSW00024163
- Location46.27°N 119.12°W
- Elevation407 ft (124 m)
- Population81,724
On October 14, the normal high in Pasco is 67°F and the normal low 39°F, and the chance of measurable rain or snow is 19%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Pasco.
- Jan 41° 28°
- Feb 49° 28°
- Mar 59° 33°
- Apr 67° 38°
- May 77° 46°
- Jun 83° 53°
- Jul 93° 57°
- Aug 91° 56°
- Sep 81° 48°
- Oct 66° 38°
- Nov 50° 32°
- Dec 41° 27°
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 Pasco each month?
July is the warmest month, with normal highs of 93°F; December the coldest, with normal lows of 27°F. The most precipitation falls in January (1.03 in), the least in July (0.15 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. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 41°F | 28°F | 34.6°F | 1.03 | 10 | <1 | 21 | 9 h |
| February | 49°F | 28°F | 38.4°F | 0.63 | 8 | <1 | 20 | 10 h 20 min |
| March | 59°F | 33°F | 45.8°F | 0.69 | 8 | <1 | 15 | 11 h 50 min |
| April | 67°F | 38°F | 52.7°F | 0.66 | 7 | <1 | 6 | 13 h 30 min |
| May | 77°F | 46°F | 61.4°F | 0.71 | 7 | 3 | 2 | 15 h |
| June | 83°F | 53°F | 67.8°F | 0.61 | 5 | 7 | <1 | 15 h 50 min |
| July | 93°F | 57°F | 74.7°F | 0.15 | 2 | 22 | <1 | 15 h 30 min |
| August | 91°F | 56°F | 73.2°F | 0.27 | 2 | 19 | <1 | 14 h 10 min |
| September | 81°F | 48°F | 64.2°F | 0.31 | 3 | 5 | <1 | 12 h 40 min |
| October | 66°F | 38°F | 52.1°F | 0.66 | 6 | <1 | 8 | 11 h |
| November | 50°F | 32°F | 40.9°F | 0.87 | 9 | <1 | 17 | 9 h 30 min |
| December | 41°F | 27°F | 34.1°F | 1.03 | 10 | <1 | 23 | 8 h 40 min |
| Year (annual) | 66°F | 40°F | 53.3°F | 7.62 | 77 | 55 | 112 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 5°C | −2°C | 1.4°C | 26 mm |
| February | 9°C | −2°C | 3.6°C | 16 mm |
| March | 15°C | 1°C | 7.7°C | 18 mm |
| April | 19°C | 4°C | 11.5°C | 17 mm |
| May | 25°C | 8°C | 16.3°C | 18 mm |
| June | 28°C | 11°C | 19.9°C | 15 mm |
| July | 34°C | 14°C | 23.7°C | 4 mm |
| August | 33°C | 13°C | 22.9°C | 7 mm |
| September | 27°C | 9°C | 17.9°C | 8 mm |
| October | 19°C | 4°C | 11.2°C | 17 mm |
| November | 10°C | 0°C | 4.9°C | 22 mm |
| December | 5°C | −3°C | 1.2°C | 26 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Ice Harbor Dam (11 miles away), gets 2 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024163; 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 Pasco?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, September has the fewest days with rain (3).
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 USW00024163.
When is the last frost in Pasco?
In Pasco, the last spring frost (32°F) comes after April 27 in half of years and after May 10 in one year in ten; the first autumn frost comes before October 11 in half of years and before September 28 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 271 year in 10 after May 10; 9 in 10 after April 8
- First autumn frost, half of years before
- October 111 year in 10 before September 28; 9 in 10 before October 27
NOAA puts the median frost-free season at 168 days, and the season without a hard freeze (28°F) at 197 days.
A hard freeze (28°F) comes after April 7 in half of springs and before October 23 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Pasco in zone 7b in ZIP code 99336, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Pasco's NOAA station is in zone 7a: the coldest night of a typical year reaches 3°F (22 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024163; 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 Pasco?
In a normal year in Pasco, 55 days a year reach 90°F (11 of them 100°F or more), 112 nights fall to 32°F or colder and 77 days bring measurable precipitation.
- Days at 90°F or more
- 55a normal year
- Days at 100°F or more
- 11a normal year
- Nights at 32°F or colder
- 112a normal year
- Days that stay below freezing
- 14high of 32°F or less
- Days with 0.01 inch of precipitation
- 77a normal year
The highest temperature in this station's record (since 1945) is 115°F, on June 27, 2021; the lowest is −19°F, on January 4, 2004.
The wettest calendar year on that record is 2010, with 10.22 in; the snowiest season is 2016–17, with 27.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024163; records: ACIS (NOAA Regional Climate Centers), station USW00024163. Records use complete months only; a month missing more than three days is left out.
How sunny is Pasco?
Over a year 81% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Pasco, 4.2 kWh per square metre a day. July is the sunniest month (94%) and December the cloudiest (55%). Among the 459 U.S. places of 50,000 or more, that ranks tied 111th (with 13 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 56% | 1.2 |
| February | 69% | 2.3 |
| March | 72% | 3.6 |
| April | 79% | 5.4 |
| May | 81% | 6.5 |
| June | 85% | 7.2 |
| July | 94% | 7.7 |
| August | 92% | 6.4 |
| September | 87% | 4.7 |
| October | 79% | 3.0 |
| November | 65% | 1.6 |
| December | 55% | 1.0 |
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 Pasco need?
A normal year in Pasco brings 5,011 heating degree days, 7% fewer than the median U.S. place (5,373), and 788 cooling degree days, 13% 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 3,103 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 942 | 0 |
| February | 745 | 0 |
| March | 594 | 0 |
| April | 371 | 2 |
| May | 150 | 39 |
| June | 33 | 118 |
| July | 3 | 304 |
| August | 5 | 259 |
| September | 86 | 63 |
| October | 403 | 3 |
| November | 723 | 0 |
| December | 956 | 0 |
| Year (annual) | 5,011 | 788 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024163. 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.
Has Pasco been warmer than normal lately?
2025 averaged 55.0°F, 1.8°F above the 1991-2020 normal of 53.3°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 56.0°F | +2.7°F | 5.42 |
| 2022 | 53.6°F | +0.3°F | 8.00 |
| 2023 | 54.7°F | +1.4°F | 5.60 |
| 2024 | 54.9°F | +1.6°F | – |
| 2025 | 55.0°F | +1.8°F | 8.45 |
Source: observed years: ACIS, station USW00024163. A year counts only with all twelve months complete.
How does Pasco's climate compare?
Pasco is warmer than 88 of the other 95 places with their own NOAA record in Washington, and wetter than 3. Across the 7,247 U.S. stations with normals, its annual mean of 53.3°F is warmer than 55%.
In the Köppen classification computed from these normals, Pasco is BSk: cold semi-arid steppe. 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 Pasco share this climate record?
West Pasco has no NOAA station with 1991-2020 normals of its 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.
- West Pasco, WA1,157 people · 3 mi W
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 Pasco's climate
What is the coldest month in Pasco?
December, with a normal high of 41°F and a normal low of 27°F. The warmest is July (93°F by day, 57°F at night).
Does it snow in Pasco?
Yes. NOAA publishes no 1991-2020 snowfall normal for Pasco's NOAA station; the nearest record that keeps one, Ice Harbor Dam (11 miles away), records 2 inches of snow in a normal year.
What is the rainiest month in Pasco?
January, with 1.03 in of precipitation in a normal year; the driest is July with 0.15 in.
What plant hardiness zone is Pasco in?
The USDA's 2023 map puts Pasco in zone 7b in ZIP code 99336, the nearest ZIP area. By the same method at Pasco's NOAA station, the coldest night of a typical year reaches 3°F (22 years, 1991-2020): zone 7a.
How late can frost come in Pasco?
In half of years the last 32°F night comes after April 27; in one year in ten it comes after May 10. Waiting until May 10 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Pasco in OctoberThis month day by day, its records and recent years
- Washington climateThe statewide normals and every place in the state
- Kennewick, WA4 miles from this station, 55.0°F a year
- Richland, WA7 miles from this station, 53.6°F a year
- Sagemoor, WA9 miles from this station, 52.0°F a year
- Eltopia (8 mi WSW), WA9 miles from this station, 51.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made