Arlington, Washington climate: Normal weather by month, frost dates and records
Arlington's normal year runs from 28°F December nights to 77°F July afternoons, with 49.0 inches of precipitation and 4 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.5°C, December lows of −2°C, July highs of 25°C, 1,244 mm of precipitation a year.
- NOAA stationArlington
- Station IDUSC00450257
- Location48.20°N 122.13°W
- Elevation100 ft (31 m)
- Population21,959
On October 23, the normal high in Arlington is 58°F and the normal low 36°F, and the chance of measurable rain or snow is 57%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Arlington.
- Jan 47° 29°
- Feb 51° 28°
- Mar 54° 32°
- Apr 60° 35°
- May 67° 41°
- Jun 71° 45°
- Jul 77° 48°
- Aug 78° 47°
- Sep 72° 42°
- Oct 61° 37°
- Nov 52° 31°
- Dec 46° 28°
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 Arlington each month?
July is the warmest month, with normal highs of 77°F; December the coldest, with normal lows of 28°F. The most precipitation falls in November (7.15 in), the least in July (1.15 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 47°F | 29°F | 38.0°F | 5.92 | 0.8 | 20 | <1 | 18 | 8 h 50 min |
| February | 51°F | 28°F | 39.3°F | 4.42 | 0.7 | 16 | <1 | 18 | 10 h 10 min |
| March | 54°F | 32°F | 42.9°F | 5.00 | 0.4 | 19 | <1 | 15 | 11 h 50 min |
| April | 60°F | 35°F | 47.6°F | 4.34 | 0.0 | 17 | <1 | 5 | 13 h 40 min |
| May | 67°F | 41°F | 53.8°F | 3.43 | 0.0 | 13 | <1 | <1 | 15 h 10 min |
| June | 71°F | 45°F | 58.2°F | 2.66 | 0.0 | 12 | 1 | <1 | 16 h |
| July | 77°F | 48°F | 62.6°F | 1.15 | 0.0 | 6 | 2 | <1 | 15 h 40 min |
| August | 78°F | 47°F | 62.4°F | 1.34 | 0.0 | 6 | 2 | <1 | 14 h 20 min |
| September | 72°F | 42°F | 57.1°F | 2.49 | 0.0 | 10 | <1 | <1 | 12 h 40 min |
| October | 61°F | 37°F | 48.9°F | 4.94 | 0.0 | 16 | <1 | 5 | 11 h |
| November | 52°F | 31°F | 41.7°F | 7.15 | 0.2 | 20 | <1 | 13 | 9 h 20 min |
| December | 46°F | 28°F | 37.0°F | 6.15 | 2.2 | 20 | <1 | 19 | 8 h 20 min |
| Year (annual) | 61°F | 37°F | 49.1°F | 48.99 | 4.3 | 176 | 5 | 94 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 9°C | −2°C | 3.3°C | 150 mm | 2 cm |
| February | 10°C | −2°C | 4.1°C | 112 mm | 2 cm |
| March | 12°C | 0°C | 6.1°C | 127 mm | 1 cm |
| April | 15°C | 2°C | 8.7°C | 110 mm | 0 cm |
| May | 19°C | 5°C | 12.1°C | 87 mm | 0 cm |
| June | 22°C | 7°C | 14.6°C | 68 mm | 0 cm |
| July | 25°C | 9°C | 17.0°C | 29 mm | 0 cm |
| August | 25°C | 8°C | 16.9°C | 34 mm | 0 cm |
| September | 22°C | 6°C | 13.9°C | 63 mm | 0 cm |
| October | 16°C | 3°C | 9.4°C | 125 mm | 0 cm |
| November | 11°C | 0°C | 5.4°C | 182 mm | 1 cm |
| December | 8°C | −2°C | 2.8°C | 156 mm | 6 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00450257; 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 Arlington?
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 (6).
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 USC00450257.
When is the last frost in Arlington?
In Arlington, the last spring frost (32°F) comes after April 22 in half of years and after May 6 in one year in ten; the first autumn frost comes before October 19 in half of years and before October 3 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 221 year in 10 after May 6; 9 in 10 after April 4
- First autumn frost, half of years before
- October 191 year in 10 before October 3; 9 in 10 before November 4
NOAA puts the median frost-free season at 181 days, and the season without a hard freeze (28°F) at 224 days.
A hard freeze (28°F) comes after March 25 in half of springs and before November 3 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Arlington in zone 8b in ZIP code 98271, the nearest ZIP area.
Frost dates for every NOAA station in Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00450257; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Arlington?
In a normal year in Arlington, 5 days a year reach 90°F, 94 nights fall to 32°F or colder and 176 days bring measurable precipitation.
- Days at 90°F or more
- 5a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 94a normal year
- Days that stay below freezing
- 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 176a normal year
- Days with 1 inch of snow or more
- 2a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00450257.
How sunny is Arlington?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Arlington, 3.5 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (51%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 52% | 1.0 |
| February | 61% | 1.9 |
| March | 61% | 2.9 |
| April | 67% | 4.3 |
| May | 71% | 5.5 |
| June | 72% | 6.0 |
| July | 82% | 6.5 |
| August | 81% | 5.5 |
| September | 76% | 3.9 |
| October | 64% | 2.2 |
| November | 55% | 1.1 |
| 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 Arlington need?
A normal year in Arlington brings 5,834 heating degree days, 9% more than the median U.S. place (5,373), and 55 cooling degree days, 94% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,458 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 837 | 0 |
| February | 721 | 0 |
| March | 687 | 0 |
| April | 524 | 0 |
| May | 348 | 0 |
| June | 211 | 7 |
| July | 98 | 23 |
| August | 101 | 21 |
| September | 240 | 3 |
| October | 501 | 0 |
| November | 699 | 0 |
| December | 868 | 0 |
| Year (annual) | 5,834 | 55 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00450257. 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 Arlington's climate compare?
Arlington is warmer than 27 of the other 95 places with their own NOAA record in Washington, and wetter than 67. Across the 7,247 U.S. stations with normals, its annual mean of 49.1°F is warmer than 36%.
In the Köppen classification computed from these normals, Arlington 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 Arlington share this climate record?
19 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.
- Marysville, WAalso near: Everett (13 mi, 51.4°F a year); Monroe (18 mi, 49.5°F a year)76,209 people · 8 mi S
- Stanwood, WA8,943 people · 10 mi W
- Lake Goodwin, WA5,682 people · 8 mi SW
- Granite Falls, WA4,702 people · 11 mi SE
- Canyon Creek, WA3,556 people · 9 mi SE
- Lake Cassidy, WA3,337 people · 10 mi S
- Warm Beach, WA3,333 people · 10 mi W
- Lochsloy, WA3,088 people · 11 mi S
- Arlington Heights, WA2,990 people · 3 mi E
- Sisco Heights, WA2,942 people · 6 mi S
- Bryant, WA2,375 people · 4 mi NW
- Kayak Point, WA1,660 people · 11 mi W
- Sunday Lake, WA1,209 people · 7 mi W
- Lake Bosworth, WA980 people · 12 mi SE
- Lake McMurray, WA533 people · 10 mi NW
- Oso, WA400 people · 11 mi NE
- Lake Cavanaugh, WA305 people · 10 mi NE
- Northwest Stanwood, WA75 people · 11 mi NW
- Silvana, WA0 people · 5 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 Arlington's climate
What is the coldest month in Arlington?
December, with a normal high of 46°F and a normal low of 28°F. The warmest is July (77°F by day, 48°F at night).
Does it snow in Arlington?
Yes: 4 inches in a normal year, falling on 2 days with 0.1 inch or more, the most in December (2.2 inches).
What is the rainiest month in Arlington?
November, with 7.15 in of precipitation in a normal year; the driest is July with 1.15 in.
What plant hardiness zone is Arlington in?
The USDA's 2023 map puts Arlington in zone 8b in ZIP code 98271, the nearest ZIP area.
How late can frost come in Arlington?
In half of years the last 32°F night comes after April 22; in one year in ten it comes after May 6. Waiting until May 6 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Washington climateThe statewide normals and every place in the state
- Mount Vernon, WA21 miles from this station, 51.5°F a year
- Sedro-Woolley, WA21 miles from this station, 51.3°F a year
- Everett, WA21 miles from this station, 51.4°F a year
- Darrington, WA24 miles from this station, 49.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made