Frost dates for Illinois City Dam, IL
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 18
typical year
Safe to plant
May 2
frost is over in 9 of 10 years
First fall frost
October 24
typical year
Growing season
188 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 21 – Apr 4 | – |
| Spinach | – | Mar 7 – 28 | Aug 29 – Sep 12 |
| Lettuce | – | Mar 21 – Apr 11 | Aug 29 – Sep 12 |
| Radishes | – | Mar 21 – May 2 | Sep 12 – 26 |
| Onions | – | Mar 21 – Apr 4 | – |
| Potatoes | – | Mar 28 – Apr 11 | – |
| Carrots | – | Mar 28 – Apr 18 | Aug 1 – 15 |
| Beets | – | Mar 21 – Apr 4 | Aug 15 – 29 |
| Kale | Feb 7 – 21 | Mar 21 – Apr 4 | Aug 15 – 29 |
| Broccoli | Feb 7 – 21 | Apr 4 – 18 | Aug 15 – 29 |
| Cabbage | Jan 24 – Feb 7 | Mar 21 – Apr 4 | Aug 15 – 29 |
| Garlic | – | – | Sep 12 – Oct 3 |
| Warm-season crops | |||
| Tomatoes | Mar 7 – 21 | May 2 – 16 | – |
| Peppers | Feb 28 – Mar 14 | May 9 – 23 | – |
| Cucumbers | – | May 2 – 23 | – |
| Zucchini | – | May 2 – 30 | – |
| Pumpkins | – | May 2 – 23 | – |
| Green beans | – | May 2 – Aug 15 | – |
| Sweet corn | – | May 2 – 30 | – |
| Basil | Mar 28 – Apr 11 | May 9 – 16 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 2 | April 18 | April 5 |
| Fall frost before | October 11 | October 24 | November 6 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 8 (April 25 in a late year), and the first one in fall around November 1.
Where these dates come from
NOAA weather station ILLINOIS CITY DAM 16, IL US (USC00114355), 1991–2020 climate normals. It's the nearest station for 3 zip codes, all within 11 miles:
52759, 61237, 61259
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.