When is the last frost in Belleville, IL?

The average last spring frost (50% probability of 32°F) in Belleville is around April 12, based on NOAA/NCEI 1991–2020 normals at the Belleville Siu Rsch, IL station (8.7 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Belleville?

The average first fall frost in Belleville, IL is around October 20, giving roughly a 189-day frost-free growing season.

What planting zone is Belleville, IL?

Belleville is in USDA plant hardiness zone 7a (average annual extreme minimum temperature 0 to 5°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Belleville?

In Belleville, IL the warmest month is July (avg high 90.2°F) and the coldest is January (avg low 24.3°F). It averages about 43.4″ of precipitation a year and 11.2″ of snow.

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Belleville, IL Planting Calendar & Frost Dates

USDA hardiness zone 7a · ZIP 62220 · elevation 137′ · NOAA & USDA data

Belleville is in USDA hardiness zone 7a (winters can dip to 0 to 5°F), with a growing season of about 189 days between the average last spring frost (April 12) and first fall frost (October 20). The warmest month is July (avg high 90.2°F); the coldest is January (avg low 24.3°F). It averages 43.4″ of precipitation a year and 11.2″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 0 to 5°F

Last spring frost

April 12

avg (50% prob, 32°F)

First fall frost

October 20

avg (50% prob, 32°F)

Growing season

189 days

frost-free window

Warmest month

July

avg high 90.2°F

Month-by-month typical weather in Belleville

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Belleville Siu Rsch, IL (8.7 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	42.9	24.3	33.6	2.6	3.4
February	48.6	28	38.3	2.2	3.3
March	59.2	36.3	47.8	3.4	1
April	70.6	46	58.3	4.9	0
May	79.1	56.3	67.7	5.1	0
June	87.3	64.5	75.9	4.6	0
July	90.2	67.8	79	4	0
August	89.1	65.3	77.2	3.9	0
September	83.3	56.9	70.1	3.4	0
October	72.6	46.7	59.7	3.1	0
November	58.1	36.9	47.5	3.6	0.6
December	46.3	28.3	37.3	2.6	2.9

What to plant when in Belleville

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 1 · Transplant out: April 19
Peppers	warm	Start seeds indoors: February 15 · Transplant out: April 26
Cucumbers	warm	Direct sow: April 19
Zucchini / squash	warm	Direct sow: April 19
Bush beans	warm	Direct sow: April 19
Sweet corn	warm	Direct sow: April 19
Basil	warm	Transplant out: April 19
Peas	cool	Sow (spring): March 8 · Sow (fall): August 25
Spinach	cool	Sow (spring): March 1 · Sow (fall): August 25
Lettuce	cool	Sow (spring): March 15 · Sow (fall): August 25
Kale	cool	Transplant (spring): March 22 · Sow (fall): August 11
Broccoli	cool	Transplant (spring): March 29
Carrots	cool	Sow (spring): March 22 · Sow (fall): August 11
Onions	cool	Transplant (spring): March 15
Potatoes	cool	Plant seed potatoes: March 29
Radishes	cool	Sow (spring): March 15 · Sow (fall): September 8

Dates are computed from Belleville's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Illinois

Springfield, IL Decatur, IL Quincy, IL Champaign, IL Urbana, IL Bloomington, IL Normal, IL Peoria, IL

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Belleville Siu Rsch, IL, 8.7 mi (confidence: high). Monthly weather normals: Belleville Siu Rsch, IL, 8.7 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.