Winter nights in New Haven are colder than in 95% of U.S. towns
On a normal July day the thermometer tops out near 82°. In July, afternoons here are cooler than in 79% of U.S. towns. December has warmed most since 1901–2000, part of a 1.6° rise. Garden chairs stay out from May to September, the months with highs of 69–82°.
A year in New Haven at a glance
Each month’s typical high and low, and what it brings.
What stands out about New Haven’s climate
Compared with towns across the U.S., with New Haven’s place in Wisconsin beside it.
What a year in New Haven feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 146 frost-free days a year
In half of years the last 32° night comes by May 8 and the first by October 3. Frost and day counts come from NOAA’s station at Wisconsin Dells, WI, 8 miles from the town’s center, at about the same height.
The 2023 USDA map puts New Haven’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −19°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 41 inches of snow a winter
Snow, measured at Wisconsin Dells, WI, falls mostly in January. Precipitation (rain plus melted snow) adds up to 36 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 111 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in New Haven
93% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Wisconsin Dells, WI.
Living with New Haven’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
146 frost-free days in zone 5a. The last frost comes by May 8 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 3.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September.
Parks & trails →Of the yearly building losses FEMA expects in New Haven from natural hazards, river flooding is the largest share (46%); heat waves, cold waves, winter storms and ice storms together are 28%. Normals are averages; the hazards page covers the extremes.
Natural hazards →New Haven and its neighbors
Every town next door is within a degree of New Haven in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like New Haven’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| New Haven, WI | 9° | 82° | 36" | 41" |
| Mason City, IA | 8° | 82° | 36" | 44" |
| Northfield, MN | 6° | 82° | 35" | 43" |
| Colchester, VT | 10° | 81° | 38" | 50" |
| Plattsburgh, NY | 9° | 81° | 35" | 50" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in New Haven averaged 1.6° warmer than the 1900s. The biggest change is in December (+3.5°).
A bigger shift than in 67% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How New Haven compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with New Haven’s place among Wisconsin’s.
New Haven weather by month
Highs, lows and precipitation from NOAA’s grid at New Haven’s center; snow, wet days and snow on the ground from Wisconsin Dells, WI. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 26° | 9° | 1.3" | 11.5" | 7 | 24 | 6° – 30° |
| February | 31° | 12° | 1.3" | 10.2" | 7 | 25 | 10° – 33° |
| March | 43° | 23° | 2.1" | 5.9" | 8 | 14 | 25° – 48° |
| April | 57° | 34° | 3.8" | 2.0" | 11 | 2 | 36° – 51° |
| May | 69° | 46° | 4.3" | 0.0" | 12 | 0 | 52° – 64° |
| June | 79° | 56° | 5.1" | 0.0" | 11 | 0 | 63° – 72° |
| July | 82° | 60° | 4.2" | 0.0" | 9 | 0 | 65° – 78° |
| August | 80° | 57° | 4.1" | 0.0" | 10 | 0 | 64° – 74° |
| September | 73° | 49° | 3.6" | 0.0" | 9 | 0 | 54° – 67° |
| October | 60° | 37° | 2.8" | 0.4" | 10 | 0 | 44° – 54° |
| November | 44° | 27° | 2.1" | 2.0" | 8 | 3 | 27° – 45° |
| December | 32° | 16° | 1.6" | 8.7" | 9 | 17 | 10° – 35° |
| Year | 56° | 35° | 36.2" | 40.7" | 111 | 85 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 10° to 35°. June is the most reliable, staying within 8°.
Where New Haven’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at New Haven’s center.
- Snow: Wisconsin Dells, WI.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Wisconsin Dells, WI, 8 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about New Haven’s climate
What is the weather like in New Haven?
A typical July afternoon reaches 82°, a January night drops to 9°, and about 41 inches of snow falls in a normal winter. Colder January nights than 95% of U.S. towns; cooler July afternoons than 79% of U.S. towns.
How cold does it get in New Haven in winter?
January nights average 9°. About 168 nights a year reach 32° or below and 26 reach 0° or below. In the coldest January of the last 30 years the month averaged 6°.
How much snow does New Haven get?
About 41 inches in a normal winter at Wisconsin Dells, WI, most of it in January, with snow on the ground about 85 days a year.
How hot does it get in New Haven?
July, with a typical high of 82° and a low of 60°. About 10 days a year reach 90° (Wisconsin Dells, WI).
When is the first and last frost in New Haven?
In half of years the last spring frost (32°) comes by May 8 and the first fall frost by October 3, about 146 frost-free days, at Wisconsin Dells, WI.
What growing zone is New Haven in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −19°.
What is the best time of year to visit New Haven?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is New Haven getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 67% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in New Haven.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.