Washington Island, Wisconsin climate: Climate normals at a NOAA weather station
Washington Island's normal year runs from 11°F January nights to 76°F July afternoons, with 30.2 inches of precipitation and 59 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.0°C, January lows of −12°C, July highs of 24°C, 767 mm of precipitation a year.
- NOAA stationWashington Island
- Station IDUSC00478905
- Location45.36°N 86.89°W
- Elevation686 ft (209 m)
On October 23, the normal high in Washington Island is 52°F and the normal low 37°F, and the chance of measurable rain or snow is 37%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Washington Island.
- Jan 26° 11°
- Feb 28° 11°
- Mar 36° 20°
- Apr 47° 30°
- May 59° 40°
- Jun 70° 50°
- Jul 76° 57°
- Aug 75° 57°
- Sep 68° 51°
- Oct 55° 40°
- Nov 42° 29°
- Dec 32° 19°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Washington Island each month?
July is the warmest month, with normal highs of 76°F; January the coldest, with normal lows of 11°F. The most precipitation falls in October (3.60 in), the least in February (1.14 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 26°F | 11°F | 18.2°F | 1.58 | 15.0 | 10 | <1 | 30 | 9 h 10 min |
| February | 28°F | 11°F | 19.1°F | 1.14 | 13.0 | 8 | <1 | 27 | 10 h 20 min |
| March | 36°F | 20°F | 27.9°F | 1.73 | 9.5 | 8 | <1 | 27 | 11 h 50 min |
| April | 47°F | 30°F | 38.6°F | 2.88 | 5.7 | 10 | <1 | 15 | 13 h 30 min |
| May | 59°F | 40°F | 49.6°F | 2.97 | 0.0 | 11 | <1 | 2 | 14 h 50 min |
| June | 70°F | 50°F | 59.9°F | 3.08 | 0.0 | 10 | <1 | <1 | 15 h 40 min |
| July | 76°F | 57°F | 66.3°F | 2.84 | 0.0 | 10 | <1 | <1 | 15 h 20 min |
| August | 75°F | 57°F | 66.2°F | 3.02 | 0.0 | 9 | <1 | <1 | 14 h 10 min |
| September | 68°F | 51°F | 59.3°F | 3.22 | 0.0 | 10 | <1 | <1 | 12 h 40 min |
| October | 55°F | 40°F | 47.2°F | 3.60 | 0.2 | 12 | <1 | 3 | 11 h |
| November | 42°F | 29°F | 35.6°F | 2.34 | 3.4 | 9 | <1 | 16 | 9 h 30 min |
| December | 32°F | 19°F | 25.6°F | 1.78 | 12.0 | 10 | <1 | 28 | 8 h 50 min |
| Year (annual) | 51°F | 35°F | 42.8°F | 30.18 | 58.8 | 116 | <1 | 149 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −4°C | −12°C | −7.7°C | 40 mm | 38 cm |
| February | −2°C | −12°C | −7.2°C | 29 mm | 33 cm |
| March | 2°C | −7°C | −2.3°C | 44 mm | 24 cm |
| April | 9°C | −1°C | 3.7°C | 73 mm | 14 cm |
| May | 15°C | 4°C | 9.8°C | 75 mm | 0 cm |
| June | 21°C | 10°C | 15.5°C | 78 mm | 0 cm |
| July | 24°C | 14°C | 19.1°C | 72 mm | 0 cm |
| August | 24°C | 14°C | 19.0°C | 77 mm | 0 cm |
| September | 20°C | 10°C | 15.2°C | 82 mm | 0 cm |
| October | 13°C | 4°C | 8.4°C | 91 mm | 1 cm |
| November | 6°C | −2°C | 2.0°C | 59 mm | 9 cm |
| December | 0°C | −7°C | −3.6°C | 45 mm | 30 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00478905; 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.
Which months are mildest at Washington Island?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August has the fewest days with rain (9).
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 USC00478905.
When is the last frost at Washington Island?
In Washington Island, the last spring frost (32°F) comes after May 15 in half of years and after May 31 in one year in ten; the first autumn frost comes before October 14 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
- May 151 year in 10 after May 31; 9 in 10 after April 30
- First autumn frost, half of years before
- October 141 year in 10 before September 28; 9 in 10 before October 31
NOAA puts the median frost-free season at 152 days, and the season without a hard freeze (28°F) at 176 days.
A hard freeze (28°F) comes after May 3 in half of springs and before October 28 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Washington Island in zone 6a in ZIP code 54246, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 6a: the coldest night of a typical year reaches −9°F (29 complete years).
Frost dates for every NOAA station in Wisconsin · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00478905; 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 at Washington Island?
In a normal year in Washington Island, a 90°F day is rare, 149 nights fall to 32°F or colder and 116 days bring measurable precipitation.
- Days at 90°F or more
- fewer than 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 149a normal year
- Days that stay below freezing
- 70high of 32°F or less
- Days with 0.01 inch of precipitation
- 116a normal year
- Days with 1 inch of snow or more
- 20a normal year
The highest temperature in this station's record (since 1944) is 97°F, on August 21, 1955; the lowest is −27°F, on January 17, 1982.
The wettest calendar year on that record is 2019, with 45.26 in; the snowiest season is 2017–18, with 100.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00478905; records: ACIS (NOAA Regional Climate Centers), station USC00478905. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Washington Island?
Over a year 71% of the sunlight that would reach the ground under clear skies gets through the clouds at Washington Island, 3.6 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (54%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 56% | 1.3 |
| February | 62% | 2.2 |
| March | 67% | 3.4 |
| April | 68% | 4.6 |
| May | 71% | 5.6 |
| June | 75% | 6.1 |
| July | 80% | 6.2 |
| August | 78% | 5.2 |
| September | 75% | 4.0 |
| October | 64% | 2.4 |
| November | 58% | 1.4 |
| December | 54% | 1.1 |
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 many heating and cooling degree days does Washington Island record?
A normal year at Washington Island brings 8,264 heating degree days, 54% more than the median U.S. place (5,373), and 210 cooling degree days, 77% 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 1,734 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,449 | 0 |
| February | 1,285 | 0 |
| March | 1,150 | 0 |
| April | 792 | 0 |
| May | 478 | 1 |
| June | 169 | 18 |
| July | 47 | 86 |
| August | 45 | 83 |
| September | 194 | 22 |
| October | 551 | 0 |
| November | 882 | 0 |
| December | 1,221 | 0 |
| Year (annual) | 8,264 | 210 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00478905. 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.
Have recent years at Washington Island been warmer than normal?
2024 averaged 46.5°F, 3.7°F above the 1991-2020 normal of 42.8°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 44.6°F | +1.8°F | 27.39 | 54.2 |
| 2022 | 42.1°F | −0.7°F | 31.80 | 72.4 |
| 2023 | 44.2°F | +1.4°F | 27.42 | 70.0 |
| 2024 | 46.5°F | +3.7°F | 28.93 | 36.2 |
Over 61 complete years from 1949 to 2024, the station's annual mean temperature rose at a fitted 4.3°F per century (+0.24°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00478905; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Washington Island's climate compare?
Washington Island is warmer than 38 of the 165 places with their own NOAA record in Wisconsin, and wetter than 9. Across the 7,247 U.S. stations with normals, its annual mean of 42.8°F is warmer than 12%.
In the Köppen classification computed from these normals, Washington Island is Dfb: continental, no dry season, 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.
Questions about Washington Island's climate
What is the coldest month at Washington Island?
January, with a normal high of 26°F and a normal low of 11°F. The warmest is July (76°F by day, 57°F at night).
Does it snow at Washington Island?
Yes: 59 inches in a normal year, falling on 32 days with 0.1 inch or more, the most in January (15.0 inches).
What is the rainiest month at Washington Island?
October, with 3.60 in of precipitation in a normal year; the driest is February with 1.14 in.
What plant hardiness zone is Washington Island in?
The USDA's 2023 map puts Washington Island in zone 6a in ZIP code 54246, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −9°F (29 years, 1991-2020): zone 6a.
How late can frost come at Washington Island?
In half of years the last 32°F night comes after May 15; in one year in ten it comes after May 31. Waiting until May 31 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wisconsin climateThe statewide normals and every place in the state
- Ephraim, WI18 miles from this station, 44.7°F a year
- Escanaba, MI27 miles from this station, 42.2°F a year
- Cornell (5 mi SE), MI35 miles from this station, 43.8°F a year
- Rapid River (4 mi SSE), MI35 miles from this station, 42.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made