Plano, IL planting zone & frost dates

Plano is in USDA hardiness zone 5b. The last spring frost usually comes around April 28 and the first fall frost around October 13, for a growing season of about 166 days.

USDA hardiness zone5bavg. extreme winter low -15°F to -10°F
Average last spring frostApril 2890% chance of no frost after May 11
Average first fall frostOctober 1310% chance of frost by September 27
Growing season166 daysfrost-free days in an average year

Planting calendar for Plano

Dates are counted from the average last spring frost (April 28) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.

CropWhen
TomatoesStart seeds indoors: Mar 3 – Mar 17
Transplant outdoors: May 5 – May 12
PeppersStart seeds indoors: Feb 17 – Mar 3
Transplant outdoors: May 12 – May 19
EggplantStart seeds indoors: Feb 17 – Mar 3
Transplant outdoors: May 12 – May 19
BroccoliStart seeds indoors: Feb 17 – Mar 3
Transplant outdoors: Mar 31 – Apr 14
CabbageStart seeds indoors: Feb 17 – Mar 3
Transplant outdoors: Mar 31 – Apr 14
Onions (sets)Plant outdoors: Mar 31 – Apr 14
PeasSow outdoors: Mar 17 – Mar 31
SpinachSow outdoors: Mar 17 – Mar 31
LettuceSow outdoors: Mar 31 – Apr 14
CarrotsSow outdoors: Mar 31 – Apr 14
PotatoesPlant outdoors: Mar 31 – Apr 14
BeansSow outdoors: May 5 – May 12
Sweet cornSow outdoors: May 5 – May 12
CucumbersSow outdoors: May 5 – May 12
Squash & zucchiniSow outdoors: May 5 – May 12
BasilStart seeds indoors: Mar 17 – Mar 31
Transplant outdoors: May 5 – May 12

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 18 (8 weeks before the average first fall frost on Oct 13).

Frost risk in detail

90% chance50% chance10% chance
Last 32°F frost in spring is afterApr 14Apr 28May 11
First 32°F frost in fall is beforeOct 24Oct 13Sep 27

How to read it: in spring there is a 10% chance of a frost after May 11, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 27. A hard freeze (28°F) usually ends around April 18.

Hardiness zone by ZIP code in Plano

Nearby cities

All cities in Illinois → · Other zone 5b cities →

Questions

What growing zone is Plano, IL?

Plano is in USDA Plant Hardiness Zone 5b (average extreme winter low -15°F to -10°F), according to the USDA 2023 map.

When is the last frost in Plano?

The average last spring frost (32°F) in Plano is April 28. There is still a 10% chance of frost until May 11.

When can I plant tomatoes in Plano?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 5 – May 12. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Chicago Aurora Muni Ap, IL (USW00004808), 12.8 km (7.9 mi) from the city center, elevation 216 m, based on 21 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.