Photo: Royalbroil · CC BY-SA 4.0Winter nights in Hartford are colder than in 93% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 81°. The wettest month is June; the driest is February. In July, afternoons here are cooler than in 86% of U.S. towns. Picnics, hikes and garden evenings come into their own from May to September, with highs of 67–81°.
A year in Hartford at a glance
Each month’s typical high and low, and what it brings.
What stands out about Hartford’s climate
Compared with towns across the U.S., with Hartford’s place in Wisconsin beside it.
What a year in Hartford feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 148 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 Hartford Wwtp, WI, 1.8 miles from the town’s center, at about the same height.
The 2023 USDA map puts Hartford’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −17°. 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 36 inches of snow a winter
Snow, measured at Hartford Wwtp, WI, falls mostly in January, February and December. Precipitation (rain plus melted snow) adds up to 35 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 115 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Hartford
95% 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 Hartford Wwtp, WI.
Living with Hartford’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
148 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. 16 miles of trails are waiting.
Parks & trails →Cold waves are 35% of the yearly building losses FEMA expects in Hartford from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Hartford and its neighbors
Every town next door is within a degree of Hartford in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Hartford’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 |
|---|---|---|---|---|
| Hartford, WI | 11° | 81° | 35" | 36" |
| Oelwein, IA | 8° | 82° | 38" | 39" |
| Woodbury, MN | 7° | 82° | 33" | 40" |
| Plattsburgh, NY | 9° | 81° | 35" | 50" |
| Colchester, VT | 10° | 81° | 38" | 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 Hartford averaged 1.1° warmer than the 1900s. The biggest change is in December (+2.8°).
A smaller shift than in 68% 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 Hartford compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Hartford’s place among Wisconsin’s.
Hartford weather by month
Highs, lows and precipitation from NOAA’s grid at Hartford’s center; snow, wet days and snow on the ground from Hartford Wwtp, WI. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 26° | 11° | 1.5" | 10.0" | 10 | 24 | 8° – 31° |
| February | 30° | 14° | 1.4" | 9.1" | 8 | 21 | 10° – 34° |
| March | 42° | 23° | 1.9" | 4.0" | 8 | 10 | 24° – 47° |
| April | 55° | 34° | 3.6" | 1.4" | 11 | 1 | 35° – 51° |
| May | 67° | 45° | 3.9" | 0.3" | 12 | 0 | 50° – 62° |
| June | 77° | 55° | 4.8" | 0.0" | 11 | 0 | 62° – 71° |
| July | 81° | 59° | 3.8" | 0.0" | 9 | 0 | 65° – 77° |
| August | 79° | 58° | 3.9" | 0.0" | 9 | 0 | 63° – 74° |
| September | 72° | 50° | 3.3" | 0.0" | 9 | 0 | 55° – 66° |
| October | 59° | 39° | 2.8" | 0.3" | 10 | 0 | 44° – 55° |
| November | 44° | 28° | 2.1" | 1.1" | 9 | 3 | 27° – 45° |
| December | 32° | 17° | 1.7" | 10.1" | 9 | 15 | 11° – 35° |
| Year | 56° | 36° | 34.8" | 36.3" | 115 | 74 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 11° to 35°. June is the most reliable, staying within 9°.
Where Hartford’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 Hartford’s center.
- Snow: Hartford Wwtp, WI (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Hartford Wwtp, WI, 1.8 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 Hartford’s climate
What is the weather like in Hartford?
A typical July afternoon reaches 81°, a January night drops to 11°, and about 36 inches of snow falls in a normal winter. Colder January nights than 93% of U.S. towns; cooler July afternoons than 86% of U.S. towns.
How cold does it get in Hartford in winter?
January nights average 11°. About 159 nights a year reach 32° or below and 22 reach 0° or below. In the coldest January of the last 30 years the month averaged 8°.
How much snow does Hartford get?
About 36 inches in a normal winter at Hartford Wwtp, WI, most of it in January, February and December, with snow on the ground about 74 days a year.
How hot does it get in Hartford?
July, with a typical high of 81° and a low of 59°. About 7 days a year reach 90° (Hartford Wwtp, WI).
When is the first and last frost in Hartford?
In half of years the last spring frost (32°) comes by May 8 and the first fall frost by October 3, about 148 frost-free days, at Hartford Wwtp, WI.
What growing zone is Hartford in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −17°.
What is the best time of year to visit Hartford?
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 Hartford getting warmer?
Yes: 1991–2020 averaged 1.1° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 68% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Hartford.
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.