Monroe, Wisconsin climate: Normal weather by month, frost dates and records
Monroe's normal year runs from 11°F January nights to 83°F July afternoons, with 39.7 inches of precipitation and 42 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.5°C, January lows of −12°C, July highs of 28°C, 1,009 mm of precipitation a year.
- NOAA stationMonroe Wastewater Treatment Plant
- Station IDUSC00475573
- Location42.60°N 89.67°W
- Elevation991 ft (302 m)
- From the center1 miles
- Population10,579
On October 14, the normal high in Monroe is 60°F and the normal low 41°F, and the chance of measurable rain or snow is 31%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Monroe.
- Jan 27° 11°
- Feb 31° 14°
- Mar 44° 25°
- Apr 57° 37°
- May 70° 49°
- Jun 79° 59°
- Jul 83° 63°
- Aug 80° 61°
- Sep 73° 52°
- Oct 59° 40°
- Nov 45° 29°
- Dec 32° 18°
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 Monroe each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 11°F. The most precipitation falls in June (6.18 in), the least in January (1.55 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 27°F | 11°F | 18.8°F | 1.55 | 11.8 | 9 | <1 | 30 | 9 h 20 min |
| February | 31°F | 14°F | 22.7°F | 1.69 | 10.5 | 8 | <1 | 27 | 10 h 30 min |
| March | 44°F | 25°F | 34.3°F | 2.12 | 4.7 | 9 | <1 | 24 | 11 h 50 min |
| April | 57°F | 37°F | 47.0°F | 3.82 | 1.4 | 11 | <1 | 10 | 13 h 20 min |
| May | 70°F | 49°F | 59.0°F | 4.07 | 0.3 | 12 | 1 | 1 | 14 h 30 min |
| June | 79°F | 59°F | 69.3°F | 6.18 | 0.0 | 12 | 4 | <1 | 15 h 20 min |
| July | 83°F | 63°F | 72.6°F | 4.15 | 0.0 | 10 | 7 | <1 | 15 h |
| August | 80°F | 61°F | 70.4°F | 4.46 | 0.0 | 10 | 3 | <1 | 14 h |
| September | 73°F | 52°F | 62.3°F | 4.15 | 0.0 | 9 | 1 | <1 | 12 h 30 min |
| October | 59°F | 40°F | 49.7°F | 3.24 | 0.4 | 10 | <1 | 9 | 11 h 10 min |
| November | 45°F | 29°F | 36.6°F | 2.39 | 1.8 | 8 | <1 | 20 | 9 h 50 min |
| December | 32°F | 18°F | 24.7°F | 1.91 | 10.6 | 9 | <1 | 29 | 9 h |
| Year (annual) | 57°F | 38°F | 47.3°F | 39.73 | 41.5 | 117 | 16 | 150 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −12°C | −7.3°C | 39 mm | 30 cm |
| February | −1°C | −10°C | −5.2°C | 43 mm | 27 cm |
| March | 6°C | −4°C | 1.3°C | 54 mm | 12 cm |
| April | 14°C | 3°C | 8.3°C | 97 mm | 4 cm |
| May | 21°C | 9°C | 15.0°C | 103 mm | 1 cm |
| June | 26°C | 15°C | 20.7°C | 157 mm | 0 cm |
| July | 28°C | 17°C | 22.6°C | 105 mm | 0 cm |
| August | 27°C | 16°C | 21.3°C | 113 mm | 0 cm |
| September | 23°C | 11°C | 16.8°C | 105 mm | 0 cm |
| October | 15°C | 5°C | 9.8°C | 82 mm | 1 cm |
| November | 7°C | −2°C | 2.6°C | 61 mm | 5 cm |
| December | 0°C | −8°C | −4.1°C | 49 mm | 27 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00475573; 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 Monroe?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September 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 USC00475573.
When is the last frost in Monroe?
In Monroe, the last spring frost (32°F) comes after April 27 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 14 in half of years and before September 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
- April 271 year in 10 after May 12; 9 in 10 after April 12
- First autumn frost, half of years before
- October 141 year in 10 before September 29; 9 in 10 before October 29
NOAA puts the median frost-free season at 170 days, and the season without a hard freeze (28°F) at 190 days.
A hard freeze (28°F) comes after April 15 in half of springs and before October 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Monroe in zone 5a in ZIP code 53566, the nearest ZIP area.
Frost dates for every NOAA station in Wisconsin · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00475573; 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 Monroe?
In a normal year in Monroe, 16 days a year reach 90°F, 150 nights fall to 32°F or colder and 117 days bring measurable precipitation.
- Days at 90°F or more
- 16a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 150a normal year
- Days that stay below freezing
- 56high of 32°F or less
- Days with 0.01 inch of precipitation
- 117a normal year
- Days with 1 inch of snow or more
- 14a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00475573.
How sunny is Monroe?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Monroe, 3.9 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 | 66% | 1.8 |
| February | 70% | 2.8 |
| March | 69% | 3.8 |
| April | 68% | 4.7 |
| May | 71% | 5.5 |
| June | 76% | 6.2 |
| July | 80% | 6.3 |
| August | 79% | 5.5 |
| September | 78% | 4.4 |
| October | 70% | 2.9 |
| November | 67% | 1.9 |
| December | 61% | 1.4 |
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 Monroe need?
A normal year in Monroe brings 7,115 heating degree days, 32% more than the median U.S. place (5,373), and 697 cooling degree days, 23% 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 2,802 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,432 | 0 |
| February | 1,184 | 0 |
| March | 951 | 1 |
| April | 544 | 2 |
| May | 227 | 42 |
| June | 33 | 162 |
| July | 8 | 242 |
| August | 15 | 181 |
| September | 141 | 61 |
| October | 479 | 6 |
| November | 852 | 0 |
| December | 1,249 | 0 |
| Year (annual) | 7,115 | 697 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00475573. 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 Monroe been warmer than normal lately?
2025 averaged 48.4°F, 1.1°F above the 1991-2020 normal of 47.3°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 49.0°F | +1.7°F | 27.94 | 34.8 |
| 2022 | 46.3°F | −1.0°F | 43.49 | 45.7 |
| 2023 | 49.6°F | +2.3°F | 30.99 | 51.9 |
| 2024 | 50.8°F | +3.5°F | 41.27 | 38.8 |
| 2025 | 48.4°F | +1.1°F | 29.12 | 33.7 |
Source: observed years: ACIS, station USC00475573. A year counts only with all twelve months complete.
How does Monroe's climate compare?
Monroe is warmer than 146 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 156. Across the 7,247 U.S. stations with normals, its annual mean of 47.3°F is warmer than 29%.
In the Köppen classification computed from these normals, Monroe is Dfa: continental, no dry season, hot 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 Monroe share this climate record?
8 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.
- Lena, IL2,666 people · 17 mi SW
- New Glarus, WI2,277 people · 15 mi N
- Monticello, WI1,179 people · 11 mi N
- Argyle, WI818 people · 12 mi NW
- Orangeville, IL739 people · 9 mi S
- Dakota, IL479 people · 16 mi SE
- Winslow, IL270 people · 10 mi SW
- Browntown, WI241 people · 6 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 Monroe's climate
What is the coldest month in Monroe?
January, with a normal high of 27°F and a normal low of 11°F. The warmest is July (83°F by day, 63°F at night).
Does it snow in Monroe?
Yes: 42 inches in a normal year, falling on 23 days with 0.1 inch or more, the most in January (11.8 inches).
What is the rainiest month in Monroe?
June, with 6.18 in of precipitation in a normal year; the driest is January with 1.55 in.
What plant hardiness zone is Monroe in?
The USDA's 2023 map puts Monroe in zone 5a in ZIP code 53566, the nearest ZIP area.
How late can frost come in Monroe?
In half of years the last 32°F night comes after April 27; in one year in ten it comes after May 12. Waiting until May 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wisconsin climateThe statewide normals and every place in the state
- Brodhead, WI14 miles from this station, 47.2°F a year
- Freeport, IL21 miles from this station, 47.7°F a year
- Stockton, IL22 miles from this station, 47.8°F a year
- Darlington, WI23 miles from this station, 46.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made