Photo: Jon Platek · CC BY-SA 3.0In Vandalia, July heat, January chill and rainfall all sit near the middle of U.S. towns
Nights in January average 22°. Summer afternoons here are warmer than in 63% of U.S. towns. Warming shows here too: 0.9° more than in 1901–2000, led by December. Radiators earn their keep from November to March, the months that average under 50°.
A year in Vandalia at a glance
Each month’s typical high and low, and what it brings.
What stands out about Vandalia’s climate
Compared with towns across the U.S., with Vandalia’s place in Illinois beside it.
What a year in Vandalia feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 196 frost-free days a year
In half of years the last 32° night comes by April 10 and the first by October 24. Frost and day counts come from NOAA’s station at Vandalia, IL, 1.4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Vandalia’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −3°. 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 13 inches of snow a winter
Snow, measured at Ramsey, IL, falls mostly in February. Precipitation (rain plus melted snow) adds up to 44 inches a year; May 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 Vandalia
81% of the work is heating. Months averaging under 55° run from November 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 Vandalia, IL.
Living with Vandalia’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
196 frost-free days in zone 6b. The last frost comes by Apr 10 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 24.
Months with highs of 62–84° and lows of 40° or more: April, May, September and October. 0.4 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Vandalia from natural hazards, river flooding is the largest share (29%); heat waves, cold waves, winter storms and ice storms together are 24%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Vandalia and its neighbors
Every town next door is within a degree of Vandalia in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Vandalia’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 |
|---|---|---|---|---|
| Vandalia, IL | 22° | 87° | 44" | 13" |
| Loveland, OH | 23° | 86° | 44" | 14" |
| Pleasant Hill, MO | 21° | 88° | 43" | 17" |
| Louisburg, KS | 21° | 88° | 41" | 14" |
| Parkersburg, WV | 24° | 86° | 44" | 11" |
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 Vandalia averaged 0.9° warmer than the 1900s. The biggest change is in December (+1.9°).
A smaller shift than in 86% 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 Vandalia compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Vandalia’s place among Illinois’.
Vandalia weather by month
Highs, lows and precipitation from NOAA’s grid at Vandalia’s center; snow, wet days and snow on the ground from Ramsey, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 37° | 22° | 2.8" | 3.6" | 9 | 10 | 23° – 40° |
| February | 43° | 25° | 2.4" | 4.4" | 9 | 6 | 22° – 44° |
| March | 53° | 34° | 3.2" | 1.6" | 10 | 2 | 36° – 57° |
| April | 66° | 43° | 4.8" | 0.3" | 11 | 0 | 47° – 61° |
| May | 76° | 54° | 4.8" | 0.0" | 12 | 0 | 60° – 73° |
| June | 84° | 63° | 4.7" | 0.0" | 10 | 0 | 68° – 77° |
| July | 87° | 66° | 4.3" | 0.0" | 9 | 0 | 72° – 84° |
| August | 86° | 64° | 3.7" | 0.0" | 8 | 0 | 70° – 81° |
| September | 80° | 56° | 3.3" | 0.0" | 7 | 0 | 64° – 73° |
| October | 68° | 45° | 3.5" | 0.0" | 9 | 0 | 52° – 62° |
| November | 53° | 35° | 3.6" | 0.5" | 9 | 1 | 36° – 51° |
| December | 42° | 26° | 2.7" | 2.4" | 9 | 5 | 20° – 43° |
| Year | 65° | 45° | 43.7" | 12.8" | 111 | 24 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 20° to 43°. June is the most reliable, staying within 9°.
Where Vandalia’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 Vandalia’s center.
- Snow: Ramsey, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Vandalia, IL, 1.4 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 Vandalia’s climate
What is the weather like in Vandalia?
A typical July afternoon reaches 87°, a January night drops to 22°, and about 13 inches of snow falls in a normal winter. Colder January nights than 52% of U.S. towns; hotter July afternoons than 63% of U.S. towns.
How cold does it get in Vandalia in winter?
January nights average 22°. About 108 nights a year reach 32° or below and 2 reach 0° or below. In the coldest January of the last 30 years the month averaged 23°.
How much snow does Vandalia get?
About 13 inches in a normal winter at Ramsey, IL, most of it in February, with snow on the ground about 24 days a year.
How hot does it get in Vandalia?
July, with a typical high of 87° and a low of 66°. About 31 days a year reach 90° (Vandalia, IL).
When is the first and last frost in Vandalia?
In half of years the last spring frost (32°) comes by April 10 and the first fall frost by October 24, about 196 frost-free days, at Vandalia, IL.
What growing zone is Vandalia in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −3°.
What is the best time of year to visit Vandalia?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Vandalia getting warmer?
Yes: 1991–2020 averaged 0.9° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 86% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Vandalia.
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.