Frost dates for Carbondale Southern Il Airport, Illinois
Half of years have their last spring frost by April 9, but 1 year in 10 still frosts after April 25.
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 25
- 1 year in 5
- April 20
- 3 years in 10
- April 16
- 2 years in 5
- April 12
- Half of years (the median)
- April 9
First fall freeze
How often the first freeze comes on or before each date.
- 1 year in 10
- October 8
- 1 year in 5
- October 13
- 3 years in 10
- October 17
- 2 years in 5
- October 19
- Half of years (the median)
- October 22
- Growing season
- about 195 days
- Hardiness zone nearby
- 7a
- Summer days
- a usual high of about 31 °C87 °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 ~5 °C42 °F · low ~-4 °C25 °F · rain ~71 mm2.8 in
- February
- high ~8 °C47 °F · low ~-2 °C28 °F · rain ~66 mm2.6 in
- March
- high ~14 °C57 °F · low ~2 °C36 °F · rain ~105 mm4.1 in
- April
- high ~20 °C68 °F · low ~7 °C45 °F · rain ~136 mm5.3 in
- May
- high ~25 °C77 °F · low ~13 °C55 °F · rain ~126 mm5 in
- June
- high ~30 °C86 °F · low ~18 °C64 °F · rain ~104 mm4.1 in
- July
- high ~31 °C88 °F · low ~20 °C67 °F · rain ~92 mm3.6 in
- August
- high ~31 °C87 °F · low ~18 °C65 °F · rain ~78 mm3.1 in
- September
- high ~27 °C81 °F · low ~13 °C56 °F · rain ~72 mm2.9 in
- October
- high ~21 °C70 °F · low ~7 °C45 °F · rain ~90 mm3.5 in
- November
- high ~13 °C56 °F · low ~2 °C35 °F · rain ~98 mm3.9 in
- December
- high ~8 °C46 °F · low ~-2 °C28 °F · rain ~79 mm3.1 in
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, the Carbondale Southern Il Airport station (listed by NOAA as Carbondale Southern Il Ap, USW00093810), at 37.78, -89.25. 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
62812, 62819, 62822, 62825, 62832, 62841, 62865, 62874, 62891, 62896, 62901, 62902…
+24 moreShow fewer
62903, 62905, 62907, 62915, 62918, 62920, 62921, 62924, 62927, 62932, 62933, 62940, 62942, 62948, 62949, 62950, 62951, 62958, 62959, 62966, 62975, 62983, 62994, 62999.
Nearby stations
The nearest stations and how their last-frost dates compare. Together they show how frost varies across your area.
- Harrisburg, IL, last frost by April 7
- Grand Chain Dam, IL, last frost by April 3
- Belleville SIU Rsch, IL, last frost by April 12
- Festus, MO, last frost by April 9
- St Louis Sci Center, MO, last frost by April 1
- Hillsboro, IL, last frost by April 13
Other stations in Illinois.
- Carlinville, IL, last frost by April 14
- Springfield #2, IL, last frost by April 15
- Decatur Airport, IL, last frost by April 16
- Rantoul, IL, last frost by April 21
- Danville, IL, last frost by April 21
- Congerville 2 NW, IL, last frost by April 21
- Peoria Greater Peoria Airport, IL, last frost by April 16
- Hennepin Wtr Trmt Plt, IL, last frost by April 24
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