Nights turn raw in Nachusa each January, colder than in 89% of U.S. towns
Midsummer highs settle at about 84°. Precipitation is light here, less than falls on 65% of U.S. towns. Since 1901–2000, the year has warmed by 1.1°, most of all in December. Garden planting can start around April 21; autumn frost returns near October 19.
A year in Nachusa at a glance
Each month’s typical high and low, and what it brings.
What stands out about Nachusa’s climate
Compared with towns across the U.S., with Nachusa’s place in Illinois beside it.
What a year in Nachusa feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 180 frost-free days a year
In half of years the last 32° night comes by April 21 and the first by October 19. Frost and day counts come from NOAA’s station at Dixon 1w, IL, 7 miles from the town’s center, 130 ft lower.
The 2023 USDA map puts Nachusa’s center in zone 5b: 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 29 inches of snow a winter
Snow, measured at Amboy, IL, falls mostly in January. Precipitation (rain plus melted snow) adds up to 39 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 110 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Nachusa
88% 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 Dixon 1w, IL.
Living with Nachusa’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
180 frost-free days in zone 5b. The last frost comes by Apr 21 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 19.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October.
Parks & trails →Of the yearly building losses FEMA expects in Nachusa from natural hazards, river flooding is the largest share (56%); heat waves, cold waves, winter storms and ice storms together are 11%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Nachusa and its neighbors
Every town next door is within a degree of Nachusa in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Nachusa’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 |
|---|---|---|---|---|
| Nachusa, IL | 13° | 84° | 39" | 29" |
| Grinnell, IA | 12° | 84° | 38" | 31" |
| Garrett, IN | 17° | 83° | 38" | 30" |
| Ghent, NY | 16° | 84° | 42" | 31" |
| Sayre, PA | 17° | 84° | 37" | 35" |
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 Nachusa averaged 1.1° warmer than the 1900s. The biggest change is in December (+2.5°).
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 Nachusa compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Nachusa’s place among Illinois’.
Nachusa weather by month
Highs, lows and precipitation from NOAA’s grid at Nachusa’s center; snow, wet days and snow on the ground from Amboy, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 13° | 1.7" | 9.8" | 8 | 17 | 12° – 34° |
| February | 34° | 18° | 1.8" | 6.9" | 7 | 11 | 12° – 37° |
| March | 47° | 28° | 2.5" | 3.8" | 8 | 4 | 29° – 53° |
| April | 61° | 38° | 3.7" | 0.9" | 11 | 0 | 40° – 56° |
| May | 72° | 49° | 4.7" | 0.0" | 13 | 0 | 54° – 67° |
| June | 81° | 59° | 5.2" | 0.0" | 11 | 0 | 66° – 74° |
| July | 84° | 62° | 4.1" | 0.0" | 9 | 0 | 67° – 79° |
| August | 82° | 60° | 4.0" | 0.0" | 10 | 0 | 65° – 77° |
| September | 76° | 53° | 3.5" | 0.0" | 8 | 0 | 58° – 69° |
| October | 63° | 41° | 3.0" | 0.0" | 10 | 0 | 47° – 58° |
| November | 47° | 30° | 2.4" | 1.0" | 8 | 1 | 31° – 48° |
| December | 35° | 19° | 2.1" | 6.5" | 8 | 9 | 13° – 38° |
| Year | 59° | 39° | 38.6" | 28.9" | 110 | 44 |
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 37°. June is the most reliable, staying within 8°.
Where Nachusa’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 Nachusa’s center.
- Snow: Amboy, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Dixon 1w, IL, 7 miles from the town’s center, 130 ft lower; 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 Nachusa’s climate
What is the weather like in Nachusa?
A typical July afternoon reaches 84°, a January night drops to 13°, and about 29 inches of snow falls in a normal winter. Colder January nights than 89% of U.S. towns; cooler July afternoons than 64% of U.S. towns.
How cold does it get in Nachusa in winter?
January nights average 13°. About 138 nights a year reach 32° or below and 13 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Nachusa get?
About 29 inches in a normal winter at Amboy, IL, most of it in January, with snow on the ground about 44 days a year.
How hot does it get in Nachusa?
July, with a typical high of 84° and a low of 62°. About 11 days a year reach 90° (Dixon 1w, IL).
When is the first and last frost in Nachusa?
In half of years the last spring frost (32°) comes by April 21 and the first fall frost by October 19, about 180 frost-free days, at Dixon 1w, IL.
What growing zone is Nachusa in?
Zone 5b 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 Nachusa?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Nachusa 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 Nachusa.
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.