Watertown, Wisconsin climate: Normal weather by month, frost dates and records
Watertown's normal year runs from 11°F January nights to 81°F July afternoons, with 37.3 inches of precipitation and 37 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.0°C, January lows of −12°C, July highs of 27°C, 946 mm of precipitation a year.
- NOAA stationWatertown Wastewater Treatment Plant
- Station IDUSC00478919
- Location43.17°N 88.74°W
- Elevation825 ft (252 m)
- Population22,617
On October 14, the normal high in Watertown is 61°F and the normal low 40°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 Watertown.
- Jan 26° 11°
- Feb 30° 13°
- Mar 42° 24°
- Apr 56° 35°
- May 68° 47°
- Jun 78° 57°
- Jul 81° 61°
- Aug 80° 59°
- Sep 73° 51°
- Oct 60° 40°
- Nov 45° 28°
- Dec 32° 17°
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 Watertown 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 (5.80 in), the least in February (1.35 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 26°F | 11°F | 18.4°F | 1.37 | 11.0 | 8 | <1 | 30 | 9 h 20 min |
| February | 30°F | 13°F | 21.8°F | 1.35 | 9.7 | 8 | <1 | 27 | 10 h 30 min |
| March | 42°F | 24°F | 33.1°F | 1.90 | 4.4 | 8 | <1 | 25 | 11 h 50 min |
| April | 56°F | 35°F | 45.4°F | 3.67 | 1.6 | 12 | <1 | 11 | 13 h 20 min |
| May | 68°F | 47°F | 57.3°F | 4.19 | 0.1 | 13 | <1 | 1 | 14 h 40 min |
| June | 78°F | 57°F | 67.4°F | 5.80 | 0.0 | 12 | 2 | <1 | 15 h 20 min |
| July | 81°F | 61°F | 71.2°F | 4.50 | 0.0 | 11 | 3 | <1 | 15 h 10 min |
| August | 80°F | 59°F | 69.3°F | 4.11 | 0.0 | 10 | 2 | <1 | 14 h |
| September | 73°F | 51°F | 61.8°F | 3.47 | 0.0 | 10 | 1 | <1 | 12 h 30 min |
| October | 60°F | 40°F | 49.6°F | 3.00 | 0.3 | 11 | <1 | 7 | 11 h 10 min |
| November | 45°F | 28°F | 36.2°F | 2.14 | 1.4 | 9 | <1 | 20 | 9 h 50 min |
| December | 32°F | 17°F | 24.7°F | 1.75 | 8.5 | 10 | <1 | 29 | 9 h |
| Year (annual) | 56°F | 37°F | 46.4°F | 37.25 | 37.0 | 123 | 7 | 149 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −12°C | −7.6°C | 35 mm | 28 cm |
| February | −1°C | −10°C | −5.7°C | 34 mm | 25 cm |
| March | 6°C | −4°C | 0.6°C | 48 mm | 11 cm |
| April | 13°C | 2°C | 7.4°C | 93 mm | 4 cm |
| May | 20°C | 8°C | 14.1°C | 106 mm | 0 cm |
| June | 25°C | 14°C | 19.7°C | 147 mm | 0 cm |
| July | 27°C | 16°C | 21.8°C | 114 mm | 0 cm |
| August | 26°C | 15°C | 20.7°C | 104 mm | 0 cm |
| September | 23°C | 10°C | 16.6°C | 88 mm | 0 cm |
| October | 15°C | 4°C | 9.8°C | 76 mm | 1 cm |
| November | 7°C | −2°C | 2.3°C | 54 mm | 4 cm |
| December | 0°C | −8°C | −4.1°C | 44 mm | 22 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00478919; 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 Watertown?
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 USC00478919.
When is the last frost in Watertown?
In Watertown, the last spring frost (32°F) comes after April 28 in half of years and after May 13 in one year in ten; the first autumn frost comes before October 12 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
- April 281 year in 10 after May 13; 9 in 10 after April 14
- First autumn frost, half of years before
- October 121 year in 10 before September 28; 9 in 10 before October 27
NOAA puts the median frost-free season at 167 days, and the season without a hard freeze (28°F) at 191 days.
A hard freeze (28°F) comes after April 16 in half of springs and before October 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Watertown in zone 5b in ZIP code 53094, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Watertown's NOAA station is in zone 5a: the coldest night of a typical year reaches −15°F (29 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 USC00478919; 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 Watertown?
In a normal year in Watertown, 7 days a year reach 90°F, 149 nights fall to 32°F or colder and 123 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
- 149a normal year
- Days that stay below freezing
- 63high of 32°F or less
- Days with 0.01 inch of precipitation
- 123a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in this station's record (since 1893) is 104°F, on July 21, 1901; the lowest is −33°F, on February 20, 1929.
The wettest calendar year on that record is 2018, with 57.53 in; the snowiest season is 1978–79, with 91.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00478919; records: ACIS (NOAA Regional Climate Centers), station USC00478919. Records use complete months only; a month missing more than three days is left out.
How sunny is Watertown?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Watertown, 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 Watertown need?
A normal year in Watertown brings 7,339 heating degree days, 37% more than the median U.S. place (5,373), and 578 cooling degree days, 36% 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 2,588 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,443 | 0 |
| February | 1,209 | 0 |
| March | 989 | 1 |
| April | 591 | 2 |
| May | 270 | 33 |
| June | 53 | 125 |
| July | 10 | 203 |
| August | 23 | 154 |
| September | 152 | 56 |
| October | 485 | 6 |
| November | 863 | 0 |
| December | 1,251 | 0 |
| Year (annual) | 7,339 | 578 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00478919. 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 Watertown been warmer than normal lately?
2025 averaged 47.0°F, 0.6°F above the 1991-2020 normal of 46.4°F. 3 of the 4 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 45.5°F | −0.9°F | 39.11 | 26.2 |
| 2023 | 48.7°F | +2.3°F | 31.42 | 43.5 |
| 2024 | 49.5°F | +3.1°F | 40.89 | 35.5 |
| 2025 | 47.0°F | +0.6°F | 29.86 | 28.1 |
Over 104 complete years from 1895 to 2025, the station's annual mean temperature rose at a fitted 3.1°F per century (+0.17°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00478919; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Watertown's climate compare?
Watertown is warmer than 116 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 128. Across the 7,247 U.S. stations with normals, its annual mean of 46.4°F is warmer than 25%.
In the Köppen classification computed from these normals, Watertown 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 Watertown's climate
What is the coldest month in Watertown?
January, with a normal high of 26°F and a normal low of 11°F. The warmest is July (81°F by day, 61°F at night).
Does it snow in Watertown?
Yes: 37 inches in a normal year, falling on 26 days with 0.1 inch or more, the most in January (11.0 inches).
What is the rainiest month in Watertown?
June, with 5.80 in of precipitation in a normal year; the driest is February with 1.35 in.
What plant hardiness zone is Watertown in?
The USDA's 2023 map puts Watertown in zone 5b in ZIP code 53094, the nearest ZIP area. By the same method at Watertown's NOAA station, the coldest night of a typical year reaches −15°F (29 years, 1991-2020): zone 5a.
How late can frost come in Watertown?
In half of years the last 32°F night comes after April 28; in one year in ten it comes after May 13. Waiting until May 13 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wisconsin climateThe statewide normals and every place in the state
- Lake Mills, WI11 miles from this station, 47.4°F a year
- Waterloo, WI12 miles from this station, 46.7°F a year
- Oconomowoc, WI13 miles from this station, 47.2°F a year
- Jefferson, WI13 miles from this station, 47.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made