Germantown, Wisconsin climate: Normal weather by month, frost dates and records
Germantown's normal year runs from 11°F January nights to 81°F July afternoons, with 34.4 inches of precipitation and 54 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.7°C, January lows of −11°C, July highs of 27°C, 873 mm of precipitation a year.
- NOAA stationGermantown
- Station IDUSC00473058
- Location43.24°N 88.12°W
- Elevation850 ft (259 m)
- From the centerunder 1 mile
- Population21,032
On October 23, the normal high in Germantown is 56°F and the normal low 36°F, and the chance of measurable rain or snow is 35%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Germantown.
- Jan 27° 11°
- Feb 31° 14°
- Mar 42° 24°
- Apr 54° 34°
- May 66° 45°
- Jun 76° 54°
- Jul 81° 60°
- Aug 79° 58°
- Sep 72° 50°
- Oct 59° 39°
- Nov 45° 28°
- Dec 33° 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 Germantown each month?
July is the warmest month, with normal highs of 81°F; January the coldest, with normal lows of 11°F. The most precipitation falls in June (4.37 in), the least in February (1.44 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 27°F | 11°F | 19.3°F | 1.57 | 16.5 | 10 | <1 | 30 | 9 h 20 min |
| February | 31°F | 14°F | 22.1°F | 1.44 | 16.0 | 8 | <1 | 27 | 10 h 30 min |
| March | 42°F | 24°F | 32.8°F | 1.90 | 6.5 | 9 | <1 | 25 | 11 h 50 min |
| April | 54°F | 34°F | 44.2°F | 3.84 | 2.0 | 11 | <1 | 12 | 13 h 20 min |
| May | 66°F | 45°F | 55.6°F | 3.95 | 0.3 | 13 | <1 | 2 | 14 h 40 min |
| June | 76°F | 54°F | 65.3°F | 4.37 | 0.0 | 12 | 1 | <1 | 15 h 20 min |
| July | 81°F | 60°F | 70.1°F | 3.92 | 0.0 | 11 | 3 | <1 | 15 h 10 min |
| August | 79°F | 58°F | 68.4°F | 3.80 | 0.0 | 11 | 2 | <1 | 14 h |
| September | 72°F | 50°F | 61.1°F | 3.22 | 0.0 | 10 | 1 | 1 | 12 h 30 min |
| October | 59°F | 39°F | 48.9°F | 2.64 | 0.3 | 12 | <1 | 9 | 11 h 10 min |
| November | 45°F | 28°F | 36.4°F | 2.00 | 2.4 | 10 | <1 | 21 | 9 h 50 min |
| December | 33°F | 18°F | 25.4°F | 1.73 | 10.3 | 9 | <1 | 29 | 9 h |
| Year (annual) | 56°F | 36°F | 45.8°F | 34.38 | 54.3 | 125 | 7 | 156 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −11°C | −7.1°C | 40 mm | 42 cm |
| February | −1°C | −10°C | −5.5°C | 37 mm | 41 cm |
| March | 5°C | −5°C | 0.4°C | 48 mm | 17 cm |
| April | 12°C | 1°C | 6.8°C | 98 mm | 5 cm |
| May | 19°C | 7°C | 13.1°C | 100 mm | 1 cm |
| June | 25°C | 12°C | 18.5°C | 111 mm | 0 cm |
| July | 27°C | 15°C | 21.2°C | 100 mm | 0 cm |
| August | 26°C | 14°C | 20.2°C | 97 mm | 0 cm |
| September | 22°C | 10°C | 16.2°C | 82 mm | 0 cm |
| October | 15°C | 4°C | 9.4°C | 67 mm | 1 cm |
| November | 7°C | −2°C | 2.4°C | 51 mm | 6 cm |
| December | 1°C | −8°C | −3.7°C | 44 mm | 26 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00473058; 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 Germantown?
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 (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 USC00473058.
When is the last frost in Germantown?
In Germantown, 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 8 in half of years and before September 26 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 22
- First autumn frost, half of years before
- October 81 year in 10 before September 26; 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 178 days.
A hard freeze (28°F) comes after April 24 in half of springs and before October 20 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Germantown in zone 5b across its 2 ZIP code areas (5b in 53022, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Germantown's NOAA station is in zone 5b: the coldest night of a typical year reaches −14°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 USC00473058; 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.
What hardiness zone is each Germantown ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Germantown's 2 ZIP code areas are all in zone 5b. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Germantown?
In a normal year in Germantown, 7 days a year reach 90°F, 156 nights fall to 32°F or colder and 125 days bring measurable precipitation.
- Days at 90°F or more
- 7a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 156a normal year
- Days that stay below freezing
- 62high of 32°F or less
- Days with 0.01 inch of precipitation
- 125a normal year
- Days with 1 inch of snow or more
- 16a normal year
The highest temperature in this station's record (since 1944) is 104°F, on July 6, 2012; the lowest is −40°F, on January 11, 1982.
The wettest calendar year on that record is 2025, with 44.64 in; the snowiest season is 2007–08, with 119.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00473058; records: ACIS (NOAA Regional Climate Centers), station USC00473058. Records use complete months only; a month missing more than three days is left out.
How sunny is Germantown?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Germantown, 3.8 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (59%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 63% | 1.6 |
| February | 70% | 2.7 |
| March | 70% | 3.7 |
| April | 68% | 4.6 |
| May | 71% | 5.5 |
| June | 76% | 6.1 |
| July | 80% | 6.3 |
| August | 78% | 5.3 |
| September | 77% | 4.2 |
| October | 68% | 2.7 |
| November | 66% | 1.8 |
| December | 59% | 1.3 |
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 Germantown need?
A normal year in Germantown brings 7,449 heating degree days, 39% more than the median U.S. place (5,373), and 493 cooling degree days, 46% 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 2,381 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,417 | 0 |
| February | 1,201 | 0 |
| March | 999 | 0 |
| April | 626 | 2 |
| May | 315 | 24 |
| June | 85 | 94 |
| July | 21 | 181 |
| August | 32 | 138 |
| September | 169 | 50 |
| October | 502 | 5 |
| November | 857 | 0 |
| December | 1,226 | 0 |
| Year (annual) | 7,449 | 493 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00473058. 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 Germantown been warmer than normal lately?
2025 averaged 46.4°F, 0.6°F above the 1991-2020 normal of 45.8°F. 2 of the 3 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 45.3°F | −0.5°F | 35.79 | 44.8 |
| 2023 | 48.4°F | +2.6°F | 29.47 | 60.2 |
| 2025 | 46.4°F | +0.6°F | 44.64 | 42.4 |
Over 69 complete years from 1945 to 2025, the station's annual mean temperature rose at a fitted 3.7°F per century (+0.21°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00473058; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Germantown's climate compare?
Germantown is warmer than 99 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 74. Across the 7,247 U.S. stations with normals, its annual mean of 45.8°F is warmer than 23%.
In the Köppen classification computed from these normals, Germantown 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 Germantown share this climate record?
2 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.
- Menomonee Falls, WI40,700 people · 5 mi S
- Mequon, WI25,329 people · 6 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 Germantown's climate
What is the coldest month in Germantown?
January, with a normal high of 27°F and a normal low of 11°F. The warmest is July (81°F by day, 60°F at night).
Does it snow in Germantown?
Yes: 54 inches in a normal year, falling on 25 days with 0.1 inch or more, the most in January (16.5 inches).
What is the rainiest month in Germantown?
June, with 4.37 in of precipitation in a normal year; the driest is February with 1.44 in.
What plant hardiness zone is Germantown in?
The USDA's 2023 map puts Germantown in zone 5b across its 2 ZIP code areas (5b in 53022, the largest). By the same method at Germantown's NOAA station, the coldest night of a typical year reaches −14°F (29 years, 1991-2020): zone 5b.
How late can frost come in Germantown?
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
- Wisconsin climateThe statewide normals and every place in the state
- Richfield, WI5 miles from this station, 46.5°F a year
- Jackson, WI6 miles from this station, 46.7°F a year
- Grafton, WI10 miles from this station, 47.9°F a year
- Slinger, WI11 miles from this station, 44.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made