Grantsburg, Wisconsin climate: Normal weather by month, frost dates and records
Grantsburg's normal year runs from 1°F January nights to 82°F July afternoons, with 33.8 inches of precipitation and 52 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.2°C, January lows of −17°C, July highs of 28°C, 858 mm of precipitation a year.
- NOAA stationGrantsburg
- Station IDUSW00014995
- Location45.77°N 92.69°W
- Elevation990 ft (302 m)
- Population1,372
On October 22, the normal high in Grantsburg is 54°F and the normal low 33°F, and the chance of measurable rain or snow is 32%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Grantsburg.
- Jan 22° 1°
- Feb 28° 5°
- Mar 41° 18°
- Apr 56° 31°
- May 69° 44°
- Jun 78° 53°
- Jul 82° 58°
- Aug 80° 56°
- Sep 72° 47°
- Oct 58° 35°
- Nov 41° 22°
- Dec 27° 10°
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 Grantsburg each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 1°F. The most precipitation falls in July (4.60 in), the least in January (0.86 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 22°F | 1°F | 11.7°F | 0.86 | 10.8 | 8 | <1 | 31 | 9 h |
| February | 28°F | 5°F | 16.6°F | 0.90 | 8.9 | 6 | <1 | 28 | 10 h 20 min |
| March | 41°F | 18°F | 29.5°F | 1.58 | 8.4 | 8 | <1 | 28 | 11 h 50 min |
| April | 56°F | 31°F | 43.1°F | 2.85 | 3.5 | 11 | <1 | 18 | 13 h 30 min |
| May | 69°F | 44°F | 56.3°F | 4.06 | 0.1 | 12 | 1 | 3 | 14 h 50 min |
| June | 78°F | 53°F | 65.8°F | 4.45 | 0.0 | 13 | 2 | <1 | 15 h 40 min |
| July | 82°F | 58°F | 70.2°F | 4.60 | 0.0 | 11 | 4 | <1 | 15 h 20 min |
| August | 80°F | 56°F | 68.1°F | 4.45 | 0.0 | 11 | 2 | <1 | 14 h 10 min |
| September | 72°F | 47°F | 59.8°F | 3.67 | 0.0 | 11 | 1 | 2 | 12 h 40 min |
| October | 58°F | 35°F | 46.3°F | 3.17 | 0.5 | 11 | <1 | 13 | 11 h |
| November | 41°F | 22°F | 31.5°F | 1.81 | 8.1 | 8 | <1 | 25 | 9 h 30 min |
| December | 27°F | 10°F | 18.4°F | 1.37 | 11.9 | 9 | <1 | 30 | 8 h 40 min |
| Year (annual) | 55°F | 32°F | 43.1°F | 33.77 | 52.2 | 119 | 9 | 177 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −5°C | −17°C | −11.3°C | 22 mm | 27 cm |
| February | −2°C | −15°C | −8.6°C | 23 mm | 23 cm |
| March | 5°C | −8°C | −1.4°C | 40 mm | 21 cm |
| April | 13°C | −1°C | 6.2°C | 72 mm | 9 cm |
| May | 21°C | 6°C | 13.5°C | 103 mm | 0 cm |
| June | 26°C | 12°C | 18.8°C | 113 mm | 0 cm |
| July | 28°C | 14°C | 21.2°C | 117 mm | 0 cm |
| August | 27°C | 13°C | 20.1°C | 113 mm | 0 cm |
| September | 22°C | 8°C | 15.4°C | 93 mm | 0 cm |
| October | 14°C | 2°C | 7.9°C | 81 mm | 1 cm |
| November | 5°C | −5°C | −0.3°C | 46 mm | 21 cm |
| December | −3°C | −12°C | −7.6°C | 35 mm | 30 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014995; 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 Grantsburg?
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 (11).
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 USW00014995.
When is the last frost in Grantsburg?
In Grantsburg, the last spring frost (32°F) comes after May 11 in half of years and after May 28 in one year in ten; the first autumn frost comes before October 1 in half of years and before September 16 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 111 year in 10 after May 28; 9 in 10 after April 27
- First autumn frost, half of years before
- October 11 year in 10 before September 16; 9 in 10 before October 14
NOAA puts the median frost-free season at 141 days, and the season without a hard freeze (28°F) at 161 days.
A hard freeze (28°F) comes after April 30 in half of springs and before October 11 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Grantsburg in zone 4a in ZIP code 54840, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Grantsburg's NOAA station is in zone 4a: the coldest night of a typical year reaches −26°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 USW00014995; 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 Grantsburg?
In a normal year in Grantsburg, 9 days a year reach 90°F, 177 nights fall to 32°F or colder and 119 days bring measurable precipitation.
- Days at 90°F or more
- 9a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 177a normal year
- Days that stay below freezing
- 78high of 32°F or less
- Days with 0.01 inch of precipitation
- 119a normal year
- Days with 1 inch of snow or more
- 17a normal year
The highest temperature in this station's record (since 1950) is 105°F, on July 16, 2006; the lowest is −44°F, on January 14, 1965.
The wettest calendar year on that record is 2019, with 43.24 in; the snowiest season is 2022–23, with 83.3 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00014995; records: ACIS (NOAA Regional Climate Centers), station USW00014995. Records use complete months only; a month missing more than three days is left out.
How sunny is Grantsburg?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Grantsburg, 3.8 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (61%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 73% | 1.8 |
| February | 79% | 2.9 |
| March | 74% | 3.9 |
| April | 69% | 4.7 |
| May | 69% | 5.4 |
| June | 74% | 6.0 |
| July | 80% | 6.3 |
| August | 78% | 5.2 |
| September | 75% | 4.0 |
| October | 67% | 2.6 |
| November | 65% | 1.6 |
| December | 61% | 1.2 |
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 Grantsburg need?
A normal year in Grantsburg brings 8,422 heating degree days, 57% more than the median U.S. place (5,373), and 479 cooling degree days, 47% 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 2,339 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,652 | 0 |
| February | 1,355 | 0 |
| March | 1,102 | 0 |
| April | 658 | 1 |
| May | 296 | 26 |
| June | 72 | 95 |
| July | 18 | 179 |
| August | 35 | 131 |
| September | 199 | 43 |
| October | 583 | 4 |
| November | 1,005 | 0 |
| December | 1,446 | 0 |
| Year (annual) | 8,422 | 479 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014995. 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 Grantsburg been warmer than normal lately?
2024 averaged 47.1°F, 4.0°F above the 1991-2020 normal of 43.1°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 45.0°F | +1.9°F | 27.40 | – |
| 2022 | 41.5°F | −1.6°F | 34.55 | 49.1 |
| 2023 | 45.6°F | +2.5°F | 32.11 | 58.3 |
| 2024 | 47.1°F | +4.0°F | 36.04 | 34.4 |
Over 53 complete years from 1951 to 2024, the station's annual mean temperature rose at a fitted 4.2°F per century (+0.23°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00014995; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Grantsburg's climate compare?
Grantsburg is warmer than 40 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 52. Across the 7,247 U.S. stations with normals, its annual mean of 43.1°F is warmer than 12%.
In the Köppen classification computed from these normals, Grantsburg 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 Grantsburg share this climate record?
5 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.
- Pine City, MN3,865 people · 14 mi W
- Rush City, MN3,353 people · 15 mi SW
- Rock Creek, MN1,778 people · 10 mi W
- Harris, MN1,142 people · 19 mi SW
- Siren, WI927 people · 15 mi E
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 Grantsburg's climate
What is the coldest month in Grantsburg?
January, with a normal high of 22°F and a normal low of 1°F. The warmest is July (82°F by day, 58°F at night).
Does it snow in Grantsburg?
Yes: 52 inches in a normal year, falling on 30 days with 0.1 inch or more, the most in December (11.9 inches).
What is the rainiest month in Grantsburg?
July, with 4.60 in of precipitation in a normal year; the driest is January with 0.86 in.
What plant hardiness zone is Grantsburg in?
The USDA's 2023 map puts Grantsburg in zone 4a in ZIP code 54840, the nearest ZIP area. By the same method at Grantsburg's NOAA station, the coldest night of a typical year reaches −26°F (29 years, 1991-2020): zone 4a.
How late can frost come in Grantsburg?
In half of years the last 32°F night comes after May 11; in one year in ten it comes after May 28. Waiting until May 28 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wisconsin climateThe statewide normals and every place in the state
- Luck, WI17 miles from this station, 44.1°F a year
- Wild River State Park, MN17 miles from this station, 42.5°F a year
- Hinckley, MN21 miles from this station, 40.4°F a year
- Danbury, WI22 miles from this station, 42.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made