Lockport, IL frost dates
Last spring frostApr 20median date
First fall frostOct 22median date
Growing season185 daysfrost-free
Hardiness zone6aZone 6a
How Lockport compares
- In 8 years out of 10, the last spring frost in Lockport falls between April 7 and May 6, a 29-day window. The first fall frost falls between October 7 and November 3.
- The median last frost is 3 days later than the Illinois median of Apr 17.
- Its 185-day growing season is longer than 44% of the 1,287 Illinois places with a regular frost season (state median 187 days).
- The last frost is 9 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 123 nights a year at or below 32°F.
- Compared with Joliet, IL, 9 km away, the last frost here is 1 day later than there and the growing season is 4 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 7 |
| 50% (median) | April 20 |
| 10% (safe for tender plants) | May 6 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 7 |
| 50% (median) | October 22 |
| 90% (late) | November 3 |
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 Lockport, IL
Lockport, IL frost dates — last frost Apr 20, first frost Oct 22, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Jan 26 to Feb 9Transplant outside: Mar 23 to Apr 6
Start indoors: Feb 9 to Feb 23Transplant outside: May 4 to May 18
Start indoors: Feb 9 to Feb 23Transplant outside: May 4 to May 18
Start indoors: Feb 23 to Mar 9Transplant outside: Apr 27 to May 11
Start indoors: Feb 23 to Mar 9Transplant outside: Mar 30 to Apr 13Sow outdoors: Mar 23 to Apr 27Plant for fall: Aug 27 to Sep 24
Start indoors: Feb 23 to Mar 9Transplant outside: Mar 23 to Apr 6Sow outdoors: Mar 23 to Apr 6Plant for fall: Aug 13 to Sep 3
Start indoors: Feb 23 to Mar 9Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 16 to Aug 6
Start indoors: Feb 23 to Mar 9Transplant outside: Mar 30 to Apr 13Plant for fall: Jul 16 to Aug 6
Start indoors: Feb 23 to Mar 9Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 9 to Mar 23Transplant outside: May 11 to May 25Sow outdoors: May 11 to May 25
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 27 to May 11
Sow outdoors: Mar 9 to Mar 30Plant for fall: Jul 30 to Aug 20
Sow outdoors: Mar 9 to Mar 30Plant for fall: Aug 27 to Sep 17
Sow outdoors: Mar 16 to Apr 27Plant for fall: Sep 10 to Oct 1
Start indoors: Mar 23 to Mar 30Transplant outside: May 4 to May 11Sow outdoors: Apr 27 to May 11Plant for fall: Aug 6 to Aug 20
Start indoors: Mar 23 to Mar 30Sow outdoors: Apr 27 to May 11Plant for fall: Aug 13 to Aug 27
Start indoors: Mar 23 to Mar 30Sow outdoors: Apr 27 to May 11
Start indoors: Mar 23 to Mar 30Transplant outside: May 4 to May 18
Sow outdoors: Mar 30 to Apr 27Plant for fall: Jul 30 to Aug 13
Sow outdoors: Mar 30 to Apr 27Plant for fall: Aug 13 to Aug 27
Sow outdoors: Mar 30 to Apr 20
Sow outdoors: Apr 6 to May 4Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 6 to Apr 27Plant for fall: Aug 27 to Sep 17
Sow outdoors: Apr 27 to May 18Plant for fall: Aug 6 to Aug 20
Sow outdoors: Apr 27 to May 11
Transplant outside: May 4 to May 25
Plant for fall: Oct 8 to Nov 12
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Lockport, IL
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 26 – Feb 9 | Mar 23 – Apr 6 | — | — |
| Peppers | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Eggplant | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Tomatoes | Feb 23 – Mar 9 | Apr 27 – May 11 | — | — |
| Lettuce | Feb 23 – Mar 9 | Mar 30 – Apr 13 | Mar 23 – Apr 27 | Aug 27 – Sep 24 |
| Kale | Feb 23 – Mar 9 | Mar 23 – Apr 6 | Mar 23 – Apr 6 | Aug 13 – Sep 3 |
| Broccoli | Feb 23 – Mar 9 | Apr 6 – Apr 20 | — | Jul 16 – Aug 6 |
| Cabbage | Feb 23 – Mar 9 | Mar 30 – Apr 13 | — | Jul 16 – Aug 6 |
| Cauliflower | Feb 23 – Mar 9 | Apr 6 – Apr 20 | — | Jul 16 – Aug 6 |
| Okra | Mar 9 – Mar 23 | May 11 – May 25 | May 11 – May 25 | — |
| Basil | Mar 9 – Mar 23 | Apr 27 – May 11 | — | — |
| Peas | — | — | Mar 9 – Mar 30 | Jul 30 – Aug 20 |
| Spinach | — | — | Mar 9 – Mar 30 | Aug 27 – Sep 17 |
| Radishes | — | — | Mar 16 – Apr 27 | Sep 10 – Oct 1 |
| Cucumbers | Mar 23 – Mar 30 | May 4 – May 11 | Apr 27 – May 11 | Aug 6 – Aug 20 |
| Zucchini & Summer Squash | Mar 23 – Mar 30 | — | Apr 27 – May 11 | Aug 13 – Aug 27 |
| Winter Squash & Pumpkins | Mar 23 – Mar 30 | — | Apr 27 – May 11 | — |
| Melons & Watermelon | Mar 23 – Mar 30 | May 4 – May 18 | — | — |
| Carrots | — | — | Mar 30 – Apr 27 | Jul 30 – Aug 13 |
| Beets | — | — | Mar 30 – Apr 27 | Aug 13 – Aug 27 |
| Potatoes | — | — | Mar 30 – Apr 20 | — |
| Swiss Chard | — | — | Apr 6 – May 4 | Aug 13 – Aug 27 |
| Cilantro | — | — | Apr 6 – Apr 27 | Aug 27 – Sep 17 |
| Green Beans | — | — | Apr 27 – May 18 | Aug 6 – Aug 20 |
| Sweet Corn | — | — | Apr 27 – May 11 | — |
| Sweet Potatoes | — | May 4 – May 25 | — | — |
| Garlic | — | — | — | Oct 8 – Nov 12 |
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 Romeoville Wfo, IL weather station, 3 km away (elevation 659 ft (201 m)).
Frost dates near Lockport
- Romeoville Apr 20 · Oct 22
- Crest Hill Apr 20 · Oct 22
- Homer Glen Apr 20 · Oct 22
- Joliet Apr 19 · Oct 25
- Bolingbrook Apr 20 · Oct 22
- New Lenox Apr 19 · Oct 25
- Plainfield Apr 20 · Oct 22
- Lemont Apr 19 · Oct 22
- Mokena Apr 20 · Oct 22
- Orland Park Apr 19 · Oct 22
Frequently asked questions
When is the last frost in Lockport, IL?
The median last spring frost in Lockport, IL is April 20. There is still about a 10% chance of frost after May 6, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Lockport, IL?
The median first fall frost is October 22, with about a 10% chance of frost before October 7.
How long is the growing season in Lockport, IL?
About 185 days between the median last spring frost and first fall frost.
What planting zone is Lockport, IL?
Lockport, IL is in USDA hardiness zone 6a.