Photo: U.S. Department of Agriculture Preston Keres/Office of Communications-Photography Services Center · Public domainLake Summerset has colder winter nights than 90% of U.S. towns
The warmest part of a July day comes in at 83° on average. Summers stay cool: July afternoons here are cooler than in 70% of U.S. towns. Warming shows here too: 1.2° more than in 1901–2000, led by December. Homes need heating from November to April, the months averaging under 50°.
A year in Lake Summerset at a glance
Each month’s typical high and low, and what it brings.
What stands out about Lake Summerset’s climate
Compared with towns across the U.S., with Lake Summerset’s place in Illinois beside it.
What a year in Lake Summerset feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 165 frost-free days a year
In half of years the last 32° night comes by April 29 and the first by October 12. Frost and day counts come from NOAA’s station at Brodhead Wwtp, WI, 11 miles from the town’s center, at about the same height.
The 2023 USDA map puts Lake Summerset’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −15°. 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 37 inches of snow a winter
Snow, measured at Brodhead Wwtp, WI, falls mostly in January, February and December. Precipitation (rain plus melted snow) adds up to 38 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 122 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Lake Summerset
91% 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 Brodhead Wwtp, WI.
Living with Lake Summerset’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
165 frost-free days in zone 5a. The last frost comes by Apr 29 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 12.
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 Lake Summerset from natural hazards, river flooding is the largest share (53%); heat waves, cold waves, winter storms and ice storms together are 15%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Lake Summerset and its neighbors
Every town next door is within a degree of Lake Summerset in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Lake Summerset’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 |
|---|---|---|---|---|
| Lake Summerset, IL | 13° | 83° | 38" | 37" |
| Grinnell, IA | 12° | 84° | 38" | 31" |
| Kendallville, IN | 17° | 83° | 38" | 36" |
| Albion, MI | 17° | 83° | 37" | 40" |
| Elmira, NY | 16° | 83° | 36" | 42" |
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 Lake Summerset averaged 1.2° warmer than the 1900s. The biggest change is in December (+2.6°).
A smaller shift than in 62% 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 Lake Summerset compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Lake Summerset’s place among Illinois’.
Lake Summerset weather by month
Highs, lows and precipitation from NOAA’s grid at Lake Summerset’s center; snow, wet days and snow on the ground from Brodhead Wwtp, WI. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 28° | 13° | 1.5" | 10.3" | 10 | 22 | 11° – 33° |
| February | 33° | 16° | 1.6" | 9.3" | 8 | 20 | 12° – 36° |
| March | 45° | 26° | 2.2" | 4.5" | 10 | 8 | 27° – 51° |
| April | 59° | 37° | 3.7" | 0.9" | 12 | 1 | 39° – 54° |
| May | 71° | 48° | 4.2" | 0.1" | 13 | 0 | 53° – 65° |
| June | 80° | 58° | 5.6" | 0.0" | 12 | 0 | 66° – 74° |
| July | 83° | 62° | 4.1" | 0.0" | 10 | 0 | 66° – 80° |
| August | 81° | 60° | 4.2" | 0.0" | 10 | 0 | 65° – 77° |
| September | 74° | 52° | 3.7" | 0.0" | 9 | 0 | 57° – 68° |
| October | 62° | 40° | 2.9" | 0.3" | 10 | 0 | 47° – 57° |
| November | 46° | 29° | 2.4" | 2.2" | 9 | 1 | 29° – 47° |
| December | 33° | 19° | 2.0" | 9.7" | 10 | 12 | 12° – 37° |
| Year | 58° | 38° | 38.2" | 37.3" | 122 | 63 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 12° to 36°. June is the most reliable, staying within 8°.
Where Lake Summerset’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 Lake Summerset’s center.
- Snow: Brodhead Wwtp, WI.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Brodhead Wwtp, WI, 11 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 Lake Summerset’s climate
What is the weather like in Lake Summerset?
A typical July afternoon reaches 83°, a January night drops to 13°, and about 37 inches of snow falls in a normal winter. Colder January nights than 90% of U.S. towns; cooler July afternoons than 70% of U.S. towns.
How cold does it get in Lake Summerset in winter?
January nights average 13°. About 151 nights a year reach 32° or below and 18 reach 0° or below. In the coldest January of the last 30 years the month averaged 11°.
How much snow does Lake Summerset get?
About 37 inches in a normal winter at Brodhead Wwtp, WI, most of it in January, February and December, with snow on the ground about 63 days a year.
How hot does it get in Lake Summerset?
July, with a typical high of 83° and a low of 62°. About 12 days a year reach 90° (Brodhead Wwtp, WI).
When is the first and last frost in Lake Summerset?
In half of years the last spring frost (32°) comes by April 29 and the first fall frost by October 12, about 165 frost-free days, at Brodhead Wwtp, WI.
What growing zone is Lake Summerset in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −15°.
What is the best time of year to visit Lake Summerset?
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 Lake Summerset getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 62% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Lake Summerset.
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.