Delavan, Wisconsin climate: Normal weather by month, frost dates and records
Delavan's normal year runs from 13°F January nights to 83°F July afternoons, with 36.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.7°C, January lows of −10°C, July highs of 28°C, 933 mm of precipitation a year.
- NOAA stationDelavan Wastewater Treatment Plant
- Station IDUSC00472051
- Location42.64°N 88.66°W
- Elevation882 ft (269 m)
- Population9,055
On October 14, the normal high in Delavan is 62°F and the normal low 40°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Delavan.
- Jan 29° 13°
- Feb 33° 16°
- Mar 44° 25°
- Apr 57° 36°
- May 69° 47°
- Jun 79° 57°
- Jul 83° 61°
- Aug 81° 59°
- Sep 74° 51°
- Oct 61° 40°
- Nov 46° 29°
- Dec 35° 20°
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 Delavan each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 13°F. The most precipitation falls in June (4.96 in), the least in January (1.56 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 29°F | 13°F | 21.3°F | 1.56 | – | <1 | 29 | 9 h 20 min |
| February | 33°F | 16°F | 24.3°F | 1.67 | – | <1 | 27 | 10 h 30 min |
| March | 44°F | 25°F | 34.3°F | 1.97 | – | <1 | 23 | 11 h 50 min |
| April | 57°F | 36°F | 46.4°F | 3.66 | – | <1 | 11 | 13 h 20 min |
| May | 69°F | 47°F | 57.9°F | 4.19 | – | 1 | 1 | 14 h 40 min |
| June | 79°F | 57°F | 67.9°F | 4.96 | – | 2 | <1 | 15 h 20 min |
| July | 83°F | 61°F | 71.9°F | 3.79 | – | 5 | <1 | 15 h |
| August | 81°F | 59°F | 70.0°F | 3.87 | – | 3 | <1 | 14 h |
| September | 74°F | 51°F | 62.7°F | 3.74 | – | 2 | <1 | 12 h 30 min |
| October | 61°F | 40°F | 50.2°F | 2.89 | – | <1 | 6 | 11 h 10 min |
| November | 46°F | 29°F | 37.6°F | 2.61 | – | <1 | 19 | 9 h 50 min |
| December | 35°F | 20°F | 27.1°F | 1.83 | – | <1 | 27 | 9 h |
| Year (annual) | 58°F | 38°F | 47.6°F | 36.74 | – | 13 | 143 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −2°C | −10°C | −5.9°C | 40 mm |
| February | 0°C | −9°C | −4.3°C | 42 mm |
| March | 7°C | −4°C | 1.3°C | 50 mm |
| April | 14°C | 2°C | 8.0°C | 93 mm |
| May | 20°C | 8°C | 14.4°C | 106 mm |
| June | 26°C | 14°C | 19.9°C | 126 mm |
| July | 28°C | 16°C | 22.2°C | 96 mm |
| August | 27°C | 15°C | 21.1°C | 98 mm |
| September | 23°C | 11°C | 17.1°C | 95 mm |
| October | 16°C | 4°C | 10.1°C | 73 mm |
| November | 8°C | −2°C | 3.1°C | 66 mm |
| December | 1°C | −7°C | −2.7°C | 46 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Lake Geneva (12 miles away), gets 40 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00472051; 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 Delavan?
Normal highs sit between 65°F and 85°F in May, June, July, August and September.
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 USC00472051.
When is the last frost in Delavan?
In Delavan, the last spring frost (32°F) comes after April 28 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 14 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 14; 9 in 10 after April 12
- First autumn frost, half of years before
- October 141 year in 10 before September 28; 9 in 10 before October 26
NOAA puts the median frost-free season at 168 days, and the season without a hard freeze (28°F) at 192 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 Delavan in zone 5b in ZIP code 53115, 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 USC00472051; 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 Delavan?
In a normal year in Delavan, 13 days a year reach 90°F and 143 nights fall to 32°F or colder.
- Days at 90°F or more
- 13a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 143a normal year
- Days that stay below freezing
- 48high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00472051.
How sunny is Delavan?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Delavan, 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 | 63% | 1.7 |
| February | 67% | 2.6 |
| March | 67% | 3.6 |
| April | 69% | 4.7 |
| May | 70% | 5.5 |
| June | 76% | 6.1 |
| July | 80% | 6.3 |
| August | 79% | 5.4 |
| September | 78% | 4.3 |
| October | 69% | 2.8 |
| November | 66% | 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 Delavan need?
A normal year in Delavan brings 6,933 heating degree days, 29% more than the median U.S. place (5,373), and 631 cooling degree days, 30% 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 2,696 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,354 | 0 |
| February | 1,140 | 0 |
| March | 953 | 2 |
| April | 561 | 1 |
| May | 254 | 32 |
| June | 41 | 128 |
| July | 9 | 221 |
| August | 19 | 174 |
| September | 138 | 69 |
| October | 464 | 4 |
| November | 824 | 0 |
| December | 1,176 | 0 |
| Year (annual) | 6,933 | 631 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00472051. 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 Delavan been warmer than normal lately?
2025 averaged 48.4°F, 0.8°F above the 1991-2020 normal of 47.6°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.2°F | +2.6°F | 22.72 |
| 2024 | 51.8°F | +4.2°F | 38.89 |
| 2025 | 48.4°F | +0.8°F | 37.07 |
Source: observed years: ACIS, station USC00472051. A year counts only with all twelve months complete.
How does Delavan's climate compare?
Delavan is warmer than 152 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 121. Across the 7,247 U.S. stations with normals, its annual mean of 47.6°F is warmer than 30%.
In the Köppen classification computed from these normals, Delavan 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 Delavan share this climate record?
10 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.
- Elkhorn, WI10,122 people · 7 mi E
- Harvard, IL9,408 people · 14 mi S
- Walworth, WI2,757 people · 8 mi SE
- Delavan Lake, WI2,728 people · 3 mi SE
- Fontana-on-Geneva Lake, WI1,861 people · 8 mi SE
- Darien, WI1,540 people · 4 mi SW
- Turtle Lake, WI307 people · 7 mi N
- Lake Lorraine, WI251 people · 8 mi NW
- Lawrence, IL213 people · 13 mi S
- Big Foot Prairie, IL0 people · 10 mi S
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 Delavan's climate
What is the coldest month in Delavan?
January, with a normal high of 29°F and a normal low of 13°F. The warmest is July (83°F by day, 61°F at night).
Does it snow in Delavan?
Yes. NOAA publishes no 1991-2020 snowfall normal for Delavan's NOAA station; the nearest record that keeps one, Lake Geneva (12 miles away), records 40 inches of snow in a normal year.
What is the rainiest month in Delavan?
June, with 4.96 in of precipitation in a normal year; the driest is January with 1.56 in.
What plant hardiness zone is Delavan in?
The USDA's 2023 map puts Delavan in zone 5b in ZIP code 53115, the nearest ZIP area.
How late can frost come in Delavan?
In half of years the last 32°F night comes after April 28; in one year in ten it comes after May 14. Waiting until May 14 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 Geneva, WI12 miles from this station, 49.4°F a year
- Clinton, WI12 miles from this station, 47.0°F a year
- Whitewater, WI15 miles from this station, 47.0°F a year
- Pell Lake, WI18 miles from this station, 47.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made