Renton, Washington climate: Normal weather by month, frost dates and records
Renton's normal year runs from 37°F December nights to 78°F August afternoons, with 34.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.0°C, December lows of 3°C, August highs of 25°C, 881 mm of precipitation a year.
- NOAA stationRenton Municipal Airport
- Station IDUSW00094248
- Location47.49°N 122.21°W
- Elevation29 ft (9 m)
- From the center1 miles
- Population105,543
On October 14, the normal high in Renton is 62°F and the normal low 47°F, and the chance of measurable rain or snow is 46%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Renton.
- Jan 48° 37°
- Feb 50° 37°
- Mar 55° 40°
- Apr 60° 43°
- May 66° 49°
- Jun 71° 54°
- Jul 77° 58°
- Aug 78° 57°
- Sep 72° 53°
- Oct 61° 46°
- Nov 52° 40°
- Dec 47° 37°
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 Renton each month?
August is the warmest month, with normal highs of 78°F; December the coldest, with normal lows of 37°F. The most precipitation falls in November (5.61 in), the least in July (0.60 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 | 48°F | 37°F | 42.5°F | 4.93 | 18 | <1 | 7 | 8 h 50 min |
| February | 50°F | 37°F | 43.6°F | 3.21 | 16 | <1 | 7 | 10 h 10 min |
| March | 55°F | 40°F | 47.1°F | 3.74 | 18 | <1 | 3 | 11 h 50 min |
| April | 60°F | 43°F | 51.3°F | 2.83 | 14 | <1 | <1 | 13 h 30 min |
| May | 66°F | 49°F | 57.6°F | 1.86 | 11 | <1 | <1 | 15 h |
| June | 71°F | 54°F | 62.3°F | 1.47 | 9 | 1 | <1 | 16 h |
| July | 77°F | 58°F | 67.3°F | 0.60 | 4 | 2 | <1 | 15 h 40 min |
| August | 78°F | 57°F | 67.5°F | 0.89 | 5 | 1 | <1 | 14 h 20 min |
| September | 72°F | 53°F | 62.4°F | 1.53 | 9 | <1 | <1 | 12 h 40 min |
| October | 61°F | 46°F | 53.7°F | 3.49 | 15 | <1 | <1 | 11 h |
| November | 52°F | 40°F | 46.2°F | 5.61 | 17 | <1 | 4 | 9 h 20 min |
| December | 47°F | 37°F | 41.8°F | 4.53 | 17 | <1 | 8 | 8 h 30 min |
| Year (annual) | 61°F | 46°F | 53.6°F | 34.69 | 153 | 4 | 30 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 9°C | 3°C | 5.8°C | 125 mm |
| February | 10°C | 3°C | 6.4°C | 82 mm |
| March | 13°C | 4°C | 8.4°C | 95 mm |
| April | 15°C | 6°C | 10.7°C | 72 mm |
| May | 19°C | 9°C | 14.2°C | 47 mm |
| June | 22°C | 12°C | 16.8°C | 37 mm |
| July | 25°C | 14°C | 19.6°C | 15 mm |
| August | 25°C | 14°C | 19.7°C | 23 mm |
| September | 22°C | 12°C | 16.9°C | 39 mm |
| October | 16°C | 8°C | 12.1°C | 89 mm |
| November | 11°C | 5°C | 7.9°C | 142 mm |
| December | 8°C | 3°C | 5.4°C | 115 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Seattle (6 miles away), gets 6 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094248; 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 Renton?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (4).
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 USW00094248.
When is the last frost in Renton?
In Renton, the last spring frost (32°F) comes after March 13 in half of years and after March 31 in one year in ten; the first autumn frost comes before November 16 in half of years and before October 29 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
- March 131 year in 10 after March 31; 9 in 10 after February 19
- First autumn frost, half of years before
- November 161 year in 10 before October 29; 9 in 10 before December 9
NOAA puts the median frost-free season at 248 days, and the season without a hard freeze (28°F) at 301 days.
A hard freeze (28°F) comes after February 13 in half of springs and before December 6 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Renton in zones 8b to 9a across its 5 ZIP code areas (9a in 98057, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Renton's NOAA station is in zone 9a: the coldest night of a typical year reaches 21°F (22 complete years).
Frost dates for every NOAA station in Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00094248; 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.
What hardiness zone is each Renton ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Renton's 5 ZIP code areas run from zone 8b to 9a: 2 in 8b and 3 in 9a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Renton?
In a normal year in Renton, 4 days a year reach 90°F, 30 nights fall to 32°F or colder and 153 days bring measurable precipitation.
- Days at 90°F or more
- 4a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 30a normal year
- Days that stay below freezing
- 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 153a normal year
The highest temperature in this station's record (since 1998) is 109°F, on June 28, 2021; the lowest is 14°F, on November 24, 2010.
The wettest calendar year on that record is 2006, with 46.94 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00094248; records: ACIS (NOAA Regional Climate Centers), station USW00094248. Records use complete months only; a month missing more than three days is left out.
How sunny is Renton?
Over a year 67% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Renton, 3.4 kWh per square metre a day. August is the sunniest month (78%) and December the cloudiest (51%). Among the 459 U.S. places of 50,000 or more, that ranks tied 452nd (with 6 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 52% | 1.0 |
| February | 60% | 1.9 |
| March | 58% | 2.9 |
| April | 63% | 4.2 |
| May | 66% | 5.3 |
| June | 68% | 5.7 |
| July | 78% | 6.3 |
| August | 78% | 5.4 |
| September | 74% | 3.9 |
| October | 63% | 2.3 |
| November | 54% | 1.2 |
| December | 51% | 0.8 |
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 Renton need?
A normal year in Renton brings 4,390 heating degree days, 18% fewer than the median U.S. place (5,373), and 258 cooling degree days, 72% 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 2,336 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 696 | 0 |
| February | 598 | 0 |
| March | 555 | 0 |
| April | 412 | 1 |
| May | 237 | 8 |
| June | 110 | 29 |
| July | 25 | 97 |
| August | 20 | 97 |
| September | 106 | 26 |
| October | 351 | 1 |
| November | 563 | 0 |
| December | 719 | 0 |
| Year (annual) | 4,390 | 258 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094248. 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 Renton been warmer than normal lately?
2023 averaged 54.9°F, 1.3°F above the 1991-2020 normal of 53.6°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 54.3°F | +0.7°F | 21.32 |
| 2022 | 53.8°F | +0.1°F | 18.24 |
| 2023 | 54.9°F | +1.3°F | 15.46 |
Source: observed years: ACIS, station USW00094248. A year counts only with all twelve months complete.
How does Renton's climate compare?
Renton is warmer than 89 of the other 95 places with their own NOAA record in Washington, and wetter than 54. Across the 7,247 U.S. stations with normals, its annual mean of 53.6°F is warmer than 55%.
In the Köppen classification computed from these normals, Renton is Csb: temperate, dry-summer, warm 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 Renton share this climate record?
6 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.
- Issaquah, WA39,664 people · 9 mi NE
- Fairwood, WA18,437 people · 5 mi SE
- Bryn Mawr-Skyway, WA17,577 people · 1 mi W
- Newcastle, WA13,072 people · 3 mi NE
- East Renton Highlands, WA12,241 people · 6 mi E
- Maple Heights-Lake Desire, WA3,694 people · 7 mi SE
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 Renton's climate
What is the coldest month in Renton?
December, with a normal high of 47°F and a normal low of 37°F. The warmest is August (78°F by day, 57°F at night).
Does it snow in Renton?
Yes. NOAA publishes no 1991-2020 snowfall normal for Renton's NOAA station; the nearest record that keeps one, Seattle (6 miles away), records 6 inches of snow in a normal year.
What is the rainiest month in Renton?
November, with 5.61 in of precipitation in a normal year; the driest is July with 0.60 in.
What plant hardiness zone is Renton in?
The USDA's 2023 map puts Renton in zones 8b to 9a across its 5 ZIP code areas (9a in 98057, the largest). By the same method at Renton's NOAA station, the coldest night of a typical year reaches 21°F (22 years, 1991-2020): zone 9a.
How late can frost come in Renton?
In half of years the last 32°F night comes after March 13; in one year in ten it comes after March 31. Waiting until March 31 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Renton in OctoberThis month day by day, its records and recent years
- Washington climateThe statewide normals and every place in the state
- Seattle Boeing Field, WA5 miles from this station, 53.8°F a year
- Kent, WA6 miles from this station, 53.8°F a year
- Seattle, WA6 miles from this station, 53.7°F a year
- Seattle Sand Point Weather Office, WA14 miles from this station, 53.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made