Mendon, IL frost dates
Last spring frostApr 14median date
First fall frostOct 23median date
Growing season192 daysfrost-free
Hardiness zone6aZone 6a
How Mendon compares
- In 8 years out of 10, the last spring frost in Mendon falls between March 30 and May 1, a 32-day window. The first fall frost falls between October 10 and November 4.
- The median last frost is 3 days earlier than the Illinois median of Apr 17.
- Its 192-day growing season is longer than 66% of the 1,287 Illinois places with a regular frost season (state median 187 days).
- The last frost is 15 days earlier than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 112 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 30 |
| 50% (median) | April 14 |
| 10% (safe for tender plants) | May 1 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 10 |
| 50% (median) | October 23 |
| 90% (late) | November 4 |
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 Mendon, IL
Mendon, IL frost dates — last frost Apr 14, first frost Oct 23, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Jan 20 to Feb 3Transplant outside: Mar 17 to Mar 31
Start indoors: Feb 3 to Feb 17Transplant outside: Apr 28 to May 12
Start indoors: Feb 3 to Feb 17Transplant outside: Apr 28 to May 12
Start indoors: Feb 17 to Mar 3Transplant outside: Apr 21 to May 5
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 24 to Apr 7Sow outdoors: Mar 17 to Apr 21Plant for fall: Aug 28 to Sep 25
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 17 to Mar 31Sow outdoors: Mar 17 to Mar 31Plant for fall: Aug 14 to Sep 4
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 31 to Apr 14Plant for fall: Jul 17 to Aug 7
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 24 to Apr 7Plant for fall: Jul 17 to Aug 7
Start indoors: Feb 17 to Mar 3Transplant outside: Mar 31 to Apr 14Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 3 to Mar 17Transplant outside: May 5 to May 19Sow outdoors: May 5 to May 19
Start indoors: Mar 3 to Mar 17Transplant outside: Apr 21 to May 5
Sow outdoors: Mar 3 to Mar 24Plant for fall: Jul 31 to Aug 21
Sow outdoors: Mar 3 to Mar 24Plant for fall: Aug 28 to Sep 18
Sow outdoors: Mar 10 to Apr 21Plant for fall: Sep 11 to Oct 2
Start indoors: Mar 17 to Mar 24Transplant outside: Apr 28 to May 5Sow outdoors: Apr 21 to May 5Plant for fall: Aug 7 to Aug 21
Start indoors: Mar 17 to Mar 24Sow outdoors: Apr 21 to May 5Plant for fall: Aug 14 to Aug 28
Start indoors: Mar 17 to Mar 24Sow outdoors: Apr 21 to May 5
Start indoors: Mar 17 to Mar 24Transplant outside: Apr 28 to May 12
Sow outdoors: Mar 24 to Apr 21Plant for fall: Jul 31 to Aug 14
Sow outdoors: Mar 24 to Apr 21Plant for fall: Aug 14 to Aug 28
Sow outdoors: Mar 24 to Apr 14
Sow outdoors: Mar 31 to Apr 28Plant for fall: Aug 14 to Aug 28
Sow outdoors: Mar 31 to Apr 21Plant for fall: Aug 28 to Sep 18
Sow outdoors: Apr 21 to May 12Plant for fall: Aug 7 to Aug 21
Sow outdoors: Apr 21 to May 5
Transplant outside: Apr 28 to May 19
Plant for fall: Oct 9 to Nov 13
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Mendon, IL
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 20 – Feb 3 | Mar 17 – Mar 31 | — | — |
| Peppers | Feb 3 – Feb 17 | Apr 28 – May 12 | — | — |
| Eggplant | Feb 3 – Feb 17 | Apr 28 – May 12 | — | — |
| Tomatoes | Feb 17 – Mar 3 | Apr 21 – May 5 | — | — |
| Lettuce | Feb 17 – Mar 3 | Mar 24 – Apr 7 | Mar 17 – Apr 21 | Aug 28 – Sep 25 |
| Kale | Feb 17 – Mar 3 | Mar 17 – Mar 31 | Mar 17 – Mar 31 | Aug 14 – Sep 4 |
| Broccoli | Feb 17 – Mar 3 | Mar 31 – Apr 14 | — | Jul 17 – Aug 7 |
| Cabbage | Feb 17 – Mar 3 | Mar 24 – Apr 7 | — | Jul 17 – Aug 7 |
| Cauliflower | Feb 17 – Mar 3 | Mar 31 – Apr 14 | — | Jul 17 – Aug 7 |
| Okra | Mar 3 – Mar 17 | May 5 – May 19 | May 5 – May 19 | — |
| Basil | Mar 3 – Mar 17 | Apr 21 – May 5 | — | — |
| Peas | — | — | Mar 3 – Mar 24 | Jul 31 – Aug 21 |
| Spinach | — | — | Mar 3 – Mar 24 | Aug 28 – Sep 18 |
| Radishes | — | — | Mar 10 – Apr 21 | Sep 11 – Oct 2 |
| Cucumbers | Mar 17 – Mar 24 | Apr 28 – May 5 | Apr 21 – May 5 | Aug 7 – Aug 21 |
| Zucchini & Summer Squash | Mar 17 – Mar 24 | — | Apr 21 – May 5 | Aug 14 – Aug 28 |
| Winter Squash & Pumpkins | Mar 17 – Mar 24 | — | Apr 21 – May 5 | — |
| Melons & Watermelon | Mar 17 – Mar 24 | Apr 28 – May 12 | — | — |
| Carrots | — | — | Mar 24 – Apr 21 | Jul 31 – Aug 14 |
| Beets | — | — | Mar 24 – Apr 21 | Aug 14 – Aug 28 |
| Potatoes | — | — | Mar 24 – Apr 14 | — |
| Swiss Chard | — | — | Mar 31 – Apr 28 | Aug 14 – Aug 28 |
| Cilantro | — | — | Mar 31 – Apr 21 | Aug 28 – Sep 18 |
| Green Beans | — | — | Apr 21 – May 12 | Aug 7 – Aug 21 |
| Sweet Corn | — | — | Apr 21 – May 5 | — |
| Sweet Potatoes | — | Apr 28 – May 19 | — | — |
| Garlic | — | — | — | Oct 9 – Nov 13 |
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 Quincy Rgnl Ap, IL weather station, 19 km away (elevation 768 ft (234 m)).
Frost dates near Mendon
- Ursa Apr 11 · Oct 23
- Paloma Apr 14 · Oct 23
- Loraine Apr 18 · Oct 21
- Coatsburg Apr 14 · Oct 23
- Fowler Apr 14 · Oct 23
- Lima Apr 11 · Oct 23
- Quincy Apr 8 · Oct 30
- Camp Point Apr 18 · Oct 21
- West Point Apr 13 · Oct 22
- Golden Apr 18 · Oct 21
Frequently asked questions
When is the last frost in Mendon, IL?
The median last spring frost in Mendon, IL is April 14. There is still about a 10% chance of frost after May 1, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Mendon, IL?
The median first fall frost is October 23, with about a 10% chance of frost before October 10.
How long is the growing season in Mendon, IL?
About 192 days between the median last spring frost and first fall frost.
What planting zone is Mendon, IL?
Mendon, IL is in USDA hardiness zone 6a.