Superior, Wisconsin climate: Normal weather by month, frost dates and records
Superior's normal year runs from 6°F January nights to 76°F July afternoons, with 31.4 inches of precipitation and 56 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.2°C, January lows of −15°C, July highs of 24°C, 799 mm of precipitation a year.
- NOAA stationSuperior
- Station IDUSC00478349
- Location46.73°N 92.07°W
- Elevation607 ft (185 m)
- Population26,620
On October 22, the normal high in Superior is 50°F and the normal low 36°F, and the chance of measurable rain or snow is 30%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Superior.
- Jan 23° 6°
- Feb 27° 9°
- Mar 36° 21°
- Apr 46° 32°
- May 57° 41°
- Jun 67° 50°
- Jul 76° 58°
- Aug 75° 58°
- Sep 67° 50°
- Oct 53° 39°
- Nov 39° 26°
- Dec 27° 13°
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 Superior each month?
July is the warmest month, with normal highs of 76°F; January the coldest, with normal lows of 6°F. The most precipitation falls in June (4.56 in), the least in January (0.81 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 | 23°F | 6°F | 14.1°F | 0.81 | 14.5 | 7 | <1 | 31 | 9 h |
| February | 27°F | 9°F | 18.0°F | 0.89 | 12.4 | 6 | <1 | 27 | 10 h 20 min |
| March | 36°F | 21°F | 28.5°F | 1.41 | 9.1 | 7 | <1 | 27 | 11 h 50 min |
| April | 46°F | 32°F | 38.9°F | 2.64 | 1.7 | 9 | <1 | 15 | 13 h 30 min |
| May | 57°F | 41°F | 49.1°F | 3.37 | 0.0 | 12 | <1 | 2 | 15 h |
| June | 67°F | 50°F | 58.2°F | 4.56 | 0.0 | 12 | 1 | <1 | 15 h 50 min |
| July | 76°F | 58°F | 67.1°F | 3.88 | 0.0 | 10 | 2 | <1 | 15 h 30 min |
| August | 75°F | 58°F | 66.4°F | 3.92 | 0.0 | 10 | 1 | <1 | 14 h 20 min |
| September | 67°F | 50°F | 58.4°F | 3.39 | 0.0 | 10 | <1 | 1 | 12 h 40 min |
| October | 53°F | 39°F | 45.8°F | 3.17 | 0.2 | 10 | <1 | 7 | 11 h |
| November | 39°F | 26°F | 32.4°F | 2.12 | 5.8 | 8 | <1 | 22 | 9 h 30 min |
| December | 27°F | 13°F | 20.2°F | 1.29 | 12.3 | 7 | <1 | 30 | 8 h 30 min |
| Year (annual) | 49°F | 34°F | 41.4°F | 31.45 | 56.0 | 106 | 3 | 161 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −5°C | −15°C | −9.9°C | 21 mm | 37 cm |
| February | −3°C | −13°C | −7.8°C | 23 mm | 31 cm |
| March | 2°C | −6°C | −1.9°C | 36 mm | 23 cm |
| April | 8°C | 0°C | 3.8°C | 67 mm | 4 cm |
| May | 14°C | 5°C | 9.5°C | 86 mm | 0 cm |
| June | 19°C | 10°C | 14.6°C | 116 mm | 0 cm |
| July | 24°C | 14°C | 19.5°C | 99 mm | 0 cm |
| August | 24°C | 14°C | 19.1°C | 100 mm | 0 cm |
| September | 19°C | 10°C | 14.7°C | 86 mm | 0 cm |
| October | 12°C | 4°C | 7.7°C | 81 mm | 1 cm |
| November | 4°C | −4°C | 0.2°C | 54 mm | 15 cm |
| December | −3°C | −10°C | −6.6°C | 33 mm | 31 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00478349; 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 Superior?
Normal highs sit between 65°F and 85°F in 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 USC00478349.
When is the last frost in Superior?
In Superior, the last spring frost (32°F) comes after May 6 in half of years and after May 25 in one year in ten; the first autumn frost comes before October 9 in half of years and before September 24 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 61 year in 10 after May 25; 9 in 10 after April 24
- First autumn frost, half of years before
- October 91 year in 10 before September 24; 9 in 10 before October 24
NOAA puts the median frost-free season at 154 days, and the season without a hard freeze (28°F) at 181 days.
A hard freeze (28°F) comes after April 24 in half of springs and before October 24 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Superior in zone 4b in ZIP code 54880. By the map's own method, the average of each year's coldest night over 1991-2020, Superior's NOAA station is in zone 5a: the coldest night of a typical year reaches −20°F (27 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 Wisconsin · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00478349; 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 Superior?
In a normal year in Superior, 3 days a year reach 90°F, 161 nights fall to 32°F or colder and 106 days bring measurable precipitation.
- Days at 90°F or more
- 3a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 161a normal year
- Days that stay below freezing
- 84high of 32°F or less
- Days with 0.01 inch of precipitation
- 106a normal year
- Days with 1 inch of snow or more
- 18a normal year
The highest temperature in this station's record (since 1909) is 105°F, on July 14, 1936; the lowest is −38°F, on February 12, 1967.
The wettest calendar year on that record is 1991, with 46.52 in; the snowiest season is 1996–97, with 91.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00478349; records: ACIS (NOAA Regional Climate Centers), station USC00478349. Records use complete months only; a month missing more than three days is left out.
How sunny is Superior?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Superior, 3.7 kWh per square metre a day. July is the sunniest month (79%) and December the cloudiest (60%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 70% | 1.6 |
| February | 76% | 2.7 |
| March | 73% | 3.8 |
| April | 69% | 4.7 |
| May | 68% | 5.4 |
| June | 72% | 5.9 |
| July | 79% | 6.2 |
| August | 77% | 5.2 |
| September | 72% | 3.8 |
| October | 65% | 2.4 |
| November | 63% | 1.5 |
| December | 60% | 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 much heating and cooling does Superior need?
A normal year in Superior brings 8,822 heating degree days, 64% more than the median U.S. place (5,373), and 267 cooling degree days, 71% 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 1,706 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,576 | 0 |
| February | 1,316 | 0 |
| March | 1,130 | 0 |
| April | 783 | 0 |
| May | 494 | 3 |
| June | 229 | 26 |
| July | 58 | 121 |
| August | 52 | 95 |
| September | 221 | 21 |
| October | 596 | 1 |
| November | 980 | 0 |
| December | 1,389 | 0 |
| Year (annual) | 8,822 | 267 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00478349. 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 Superior been warmer than normal lately?
2025 averaged 42.4°F, 1.0°F above the 1991-2020 normal of 41.4°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 44.7°F | +3.3°F | 22.98 | 30.2 |
| 2022 | 40.2°F | −1.2°F | 24.28 | 44.2 |
| 2023 | 43.6°F | +2.2°F | 29.71 | 52.0 |
| 2024 | 46.1°F | +4.8°F | 26.67 | 16.0 |
| 2025 | 42.4°F | +1.0°F | 19.82 | 45.5 |
Over 46 complete years from 1950 to 2025, the station's annual mean temperature rose at a fitted 6.9°F per century (+0.38°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00478349; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Superior's climate compare?
Superior is warmer than 19 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 17. Across the 7,247 U.S. stations with normals, its annual mean of 41.4°F is warmer than 8%.
In the Köppen classification computed from these normals, Superior 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.
Which places near Superior share this climate record?
3 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.
- Rice Lake, MN4,168 people · 13 mi N
- Proctor, MN3,076 people · 7 mi W
- Esko, MN2,063 people · 14 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 Superior's climate
What is the coldest month in Superior?
January, with a normal high of 23°F and a normal low of 6°F. The warmest is July (76°F by day, 58°F at night).
Does it snow in Superior?
Yes: 56 inches in a normal year, falling on 26 days with 0.1 inch or more, the most in January (14.5 inches).
What is the rainiest month in Superior?
June, with 4.56 in of precipitation in a normal year; the driest is January with 0.81 in.
What plant hardiness zone is Superior in?
The USDA's 2023 map puts Superior in zone 4b in ZIP code 54880. By the same method at Superior's NOAA station, the coldest night of a typical year reaches −20°F (27 years, 1991-2020): zone 5a.
How late can frost come in Superior?
In half of years the last 32°F night comes after May 6; in one year in ten it comes after May 25. Waiting until May 25 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Superior in OctoberThis month day by day, its records and recent years
- Wisconsin climateThe statewide normals and every place in the state
- Duluth, MN10 miles from this station, 40.6°F a year
- Hermantown, MN10 miles from this station, 39.7°F a year
- Pattison Ranger Staion, WI13 miles from this station, 40.7°F a year
- Foxboro, WI19 miles from this station, 39.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made