Frost dates for Belleville SIU Rsch, Illinois
Half of years have their last spring frost by April 12, but 1 year in 10 still frosts after April 28.
A frost date is really a percentile from 30 years of records at a nearby weather station: in about half of years a frost still comes after the median date. Both numbers are below, so you can choose the risk yourself.
The odds
Last spring frost
How often a frost still comes on or after each date.
- 1 year in 10
- April 28
- 1 year in 5
- April 22
- 3 years in 10
- April 19
- 2 years in 5
- April 15
- Half of years (the median)
- April 12
First fall freeze
How often the first freeze comes on or before each date.
- 1 year in 10
- October 3
- 1 year in 5
- October 10
- 3 years in 10
- October 14
- 2 years in 5
- October 17
- Half of years (the median)
- October 20
- Growing season
- about 189 days
- Hardiness zones nearby
- 6b, 7a
- Summer days
- a usual high of about 32 °C89 °F
- Lettuce and spinach run to seed
- May to September, in hot, long days (how we know)
Summer and rain
A growing garden needs about 25 mm1 in of water a week, rain and watering together. Here is what a normal month brings.
Month by month
- January
- high ~6 °C43 °F · low ~-4 °C24 °F · rain ~65 mm2.6 in
- February
- high ~9 °C49 °F · low ~-2 °C28 °F · rain ~55 mm2.2 in
- March
- high ~15 °C59 °F · low ~2 °C36 °F · rain ~87 mm3.4 in
- April
- high ~21 °C71 °F · low ~8 °C46 °F · rain ~124 mm4.9 in
- May
- high ~26 °C79 °F · low ~14 °C56 °F · rain ~128 mm5.1 in
- June
- high ~31 °C87 °F · low ~18 °C65 °F · rain ~117 mm4.6 in
- July
- high ~32 °C90 °F · low ~20 °C68 °F · rain ~102 mm4 in
- August
- high ~32 °C89 °F · low ~18 °C65 °F · rain ~100 mm3.9 in
- September
- high ~28 °C83 °F · low ~14 °C57 °F · rain ~85 mm3.4 in
- October
- high ~23 °C73 °F · low ~8 °C47 °F · rain ~79 mm3.1 in
- November
- high ~14 °C58 °F · low ~3 °C37 °F · rain ~91 mm3.6 in
- December
- high ~8 °C46 °F · low ~-2 °C28 °F · rain ~66 mm2.6 in
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, the Belleville SIU Rsch station (listed by NOAA as Belleville SIU Rsch, USW00013802), at 38.52, -89.85. These are that station’s own records, unshifted. The further your garden is from it, the less exactly they describe your ground. The planner finds the nearest station to your garden and lowers its confidence with distance, so no number is presented as if it were measured in your garden.
Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a few hundred feet away does not. No table can know that about your garden. A few seasons of your own logged frosts can.
ZIP codes nearest this station
62061, 62208, 62215, 62220, 62221, 62223, 62225, 62226, 62232, 62234, 62243, 62248…
+13 moreShow fewer
62254, 62258, 62260, 62264, 62265, 62266, 62269, 62281, 62282, 62285, 62289, 62293, 62294.
Nearby stations
The nearest stations and how their last-frost dates compare. Together they show how frost varies across your area.
- St Louis Sci Center, MO, last frost by April 1
- Festus, MO, last frost by April 9
- Weldon Spring NWS, MO, last frost by April 10
- Hillsboro, IL, last frost by April 13
- Carlinville, IL, last frost by April 14
- Carbondale Southern Il Airport, IL, last frost by April 9
Other stations in Illinois.
- Springfield #2, IL, last frost by April 15
- Harrisburg, IL, last frost by April 7
- Grand Chain Dam, IL, last frost by April 3
- Decatur Airport, IL, last frost by April 16
- Peoria Greater Peoria Airport, IL, last frost by April 16
- Congerville 2 NW, IL, last frost by April 21
- Rantoul, IL, last frost by April 21
- Danville, IL, last frost by April 21
When do I plant? · Where the dates come from
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