Roscoe, IL frost dates
Last spring frostMay 1median date
First fall frostOct 12median date
Growing season164 daysfrost-free
Hardiness zone5bZone 5b
How Roscoe compares
- In 8 years out of 10, the last spring frost in Roscoe falls between April 17 and May 16, a 29-day window. The first fall frost falls between September 28 and October 24.
- The median last frost is 14 days later than the Illinois median of Apr 17.
- Its 164-day growing season is among the shortest of the 1,287 Illinois places with a regular frost season.
- The last frost is typical for zone 5b, where the median is May 1.
- The weather station records an average of 142 nights a year at or below 32°F.
- Compared with Rockford, IL, 17 km away, the last frost here is 7 days later than there and the growing season is 12 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 17 |
| 50% (median) | May 1 |
| 10% (safe for tender plants) | May 16 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 28 |
| 50% (median) | October 12 |
| 90% (late) | October 24 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Roscoe, IL
Roscoe, IL frost dates — last frost May 1, first frost Oct 12, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Feb 6 to Feb 20Transplant outside: Apr 3 to Apr 17
Start indoors: Feb 20 to Mar 6Transplant outside: May 15 to May 29
Start indoors: Feb 20 to Mar 6Transplant outside: May 15 to May 29
Start indoors: Mar 6 to Mar 20Transplant outside: May 8 to May 22
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 10 to Apr 24Sow outdoors: Apr 3 to May 8Plant for fall: Aug 17 to Sep 14
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 3 to Apr 17Sow outdoors: Apr 3 to Apr 17Plant for fall: Aug 3 to Aug 24
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 17 to May 1Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 17 to May 1Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5Sow outdoors: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Mar 20 to Apr 10Plant for fall: Jul 20 to Aug 10
Sow outdoors: Mar 20 to Apr 10Plant for fall: Aug 17 to Sep 7
Sow outdoors: Mar 27 to May 8Plant for fall: Aug 31 to Sep 21
Start indoors: Apr 3 to Apr 10Transplant outside: May 15 to May 22Sow outdoors: May 8 to May 22Plant for fall: Jul 27 to Aug 10
Start indoors: Apr 3 to Apr 10Sow outdoors: May 8 to May 22Plant for fall: Aug 3 to Aug 17
Start indoors: Apr 3 to Apr 10Sow outdoors: May 8 to May 22
Start indoors: Apr 3 to Apr 10Transplant outside: May 15 to May 29
Sow outdoors: Apr 10 to May 8Plant for fall: Jul 20 to Aug 3
Sow outdoors: Apr 10 to May 8Plant for fall: Aug 3 to Aug 17
Sow outdoors: Apr 10 to May 1
Sow outdoors: Apr 17 to May 15Plant for fall: Aug 3 to Aug 17
Sow outdoors: Apr 17 to May 8Plant for fall: Aug 17 to Sep 7
Sow outdoors: May 8 to May 29Plant for fall: Jul 27 to Aug 10
Sow outdoors: May 8 to May 22
Transplant outside: May 15 to Jun 5
Plant for fall: Sep 28 to Nov 2
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Roscoe, IL
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 6 – Feb 20 | Apr 3 – Apr 17 | — | — |
| Peppers | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Eggplant | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Tomatoes | Mar 6 – Mar 20 | May 8 – May 22 | — | — |
| Lettuce | Mar 6 – Mar 20 | Apr 10 – Apr 24 | Apr 3 – May 8 | Aug 17 – Sep 14 |
| Kale | Mar 6 – Mar 20 | Apr 3 – Apr 17 | Apr 3 – Apr 17 | Aug 3 – Aug 24 |
| Broccoli | Mar 6 – Mar 20 | Apr 17 – May 1 | — | Jul 6 – Jul 27 |
| Cabbage | Mar 6 – Mar 20 | Apr 10 – Apr 24 | — | Jul 6 – Jul 27 |
| Cauliflower | Mar 6 – Mar 20 | Apr 17 – May 1 | — | Jul 6 – Jul 27 |
| Okra | Mar 20 – Apr 3 | May 22 – Jun 5 | May 22 – Jun 5 | — |
| Basil | Mar 20 – Apr 3 | May 8 – May 22 | — | — |
| Peas | — | — | Mar 20 – Apr 10 | Jul 20 – Aug 10 |
| Spinach | — | — | Mar 20 – Apr 10 | Aug 17 – Sep 7 |
| Radishes | — | — | Mar 27 – May 8 | Aug 31 – Sep 21 |
| Cucumbers | Apr 3 – Apr 10 | May 15 – May 22 | May 8 – May 22 | Jul 27 – Aug 10 |
| Zucchini & Summer Squash | Apr 3 – Apr 10 | — | May 8 – May 22 | Aug 3 – Aug 17 |
| Winter Squash & Pumpkins | Apr 3 – Apr 10 | — | May 8 – May 22 | — |
| Melons & Watermelon | Apr 3 – Apr 10 | May 15 – May 29 | — | — |
| Carrots | — | — | Apr 10 – May 8 | Jul 20 – Aug 3 |
| Beets | — | — | Apr 10 – May 8 | Aug 3 – Aug 17 |
| Potatoes | — | — | Apr 10 – May 1 | — |
| Swiss Chard | — | — | Apr 17 – May 15 | Aug 3 – Aug 17 |
| Cilantro | — | — | Apr 17 – May 8 | Aug 17 – Sep 7 |
| Green Beans | — | — | May 8 – May 29 | Jul 27 – Aug 10 |
| Sweet Corn | — | — | May 8 – May 22 | — |
| Sweet Potatoes | — | May 15 – Jun 5 | — | — |
| Garlic | — | — | — | Sep 28 – Nov 2 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Beloit, WI weather station, 10 km away (elevation 787 ft (240 m)).
Frost dates near Roscoe
- South Beloit May 1 · Oct 12
- Caledonia May 1 · Oct 12
- Machesney Park May 1 · Oct 12
- Rockton May 1 · Oct 12
- Poplar Grove Apr 30 · Oct 10
- Loves Park Apr 24 · Oct 17
- Shirland May 1 · Oct 12
- Rockford Apr 24 · Oct 17
- Capron Apr 30 · Oct 10
- Belvidere Apr 28 · Oct 12
Frequently asked questions
When is the last frost in Roscoe, IL?
The median last spring frost in Roscoe, IL is May 1. There is still about a 10% chance of frost after May 16, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Roscoe, IL?
The median first fall frost is October 12, with about a 10% chance of frost before September 28.
How long is the growing season in Roscoe, IL?
About 164 days between the median last spring frost and first fall frost.
What planting zone is Roscoe, IL?
Roscoe, IL is in USDA hardiness zone 5b.