Last frost date in Collinsville, IL
Expect the last frost in Collinsville around April 8. Frost after April 23 happens in only one year out of ten. The first fall frost usually arrives about October 26, which leaves 200 frost-free days. An early freeze before October 12 happens one year in ten.
- Safe after (10% risk)
- Apr 23
- Average first frost
- Oct 26
- Frost-free season
- 200 days
- Hard freeze (28°F) ends
- Mar 28
No frost in the next 7 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2248°
- FriOct 2346°
- SatOct 2448°
- SunOct 2551°
- MonOct 2650°
- TueOct 2748°
- WedOct 2848°
Planting calendar for Collinsville
Windows count forward or back from the average frost dates above. Click a crop for dates across Illinois.
TomatoesApr 15–Apr 29
PumpkinsApr 22–May 6
SunflowersApr 8–Apr 29
CucumbersApr 22–Apr 29
CornApr 15–Apr 29
Sweet potatoesApr 29–May 13
WatermelonApr 22–May 6
Green beansApr 15–May 6
ZucchiniApr 15–Apr 29
OkraApr 29–May 13
PeppersApr 22–May 6
BasilApr 15–Apr 29
Butternut squashApr 15–Apr 29
CantaloupeApr 22–May 6
EggplantApr 22–May 6
PotatoesMar 11–Mar 25
OnionsFeb 25–Mar 18
CarrotsMar 18–Apr 22
LettuceMar 25–Apr 15
BroccoliMar 11–Mar 25
BeetsMar 11–Apr 22
PeasFeb 25–Mar 11
CabbageMar 11–Mar 25
RadishesMar 4–Apr 15
Brussels sproutsMar 25–Apr 8
SpinachFeb 25–Mar 18
CilantroMar 25–Apr 15
KaleMar 11–Mar 25
Collard greensMar 11–Mar 25
TurnipsMar 11–Mar 25
DillApr 8–Apr 22
CeleryApr 15–Apr 22
CauliflowerMar 25–Apr 8
LeeksMar 25–Apr 8
Swiss chardMar 25–Apr 22
ParsleyMar 25–Apr 15
Tulip bulbsOct 12–Nov 16
GarlicOct 5–Nov 9
Daffodil bulbsSep 28–Nov 9
StrawberriesMar 11–Mar 25
AsparagusMar 11–Mar 25Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Mar 23 | Apr 8 | Apr 23 | Oct 12 | Oct 26 | Nov 7 |
| Hard freeze, 28°F | Mar 10 | Mar 28 | Apr 12 | Oct 24 | Nov 6 | Nov 24 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Cahokia St Louis Airport (USW00003960) sits 10.9 miles from the center of Collinsville at 413 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Collinsville, IL?
The average last frost date in Collinsville is April 8, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 23.
When is the first frost in Collinsville?
The first frost in fall usually comes around October 26. One year in ten it arrives before October 12.
How long is the growing season in Collinsville?
About 200 days between the average last and first frost.
When should I plant tomatoes in Collinsville?
Plant tomato seedlings outside from April 15 to April 29. Start seeds indoors six to eight weeks earlier.
Nearby in Illinois
- Granite CityApr 4
- O'FallonApr 12
- EdwardsvilleApr 4
- BellevilleApr 12
- AltonApr 4
- CarbondaleApr 9
- SpringfieldApr 15
- DecaturApr 14
- QuincyApr 8
- PekinApr 16
- ChampaignApr 15
- BloomingtonApr 25