When to plant in Markham, IL
USDA Zone 6aEverything below — frost dates, hardiness zone, and what to plant when in Markham, Illinois — is derived from the closest NOAA station with complete climate normals.
In zone 6a, Markham gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
PARK FOREST · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Markham’s own odds, recorded at PARK FOREST.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 24 | May 5 | Apr 20 | Sep 27 | Oct 10 | Oct 22 |
| 32°F | May 11 | Apr 23 | Apr 9 | Oct 6 | Oct 20 | Nov 1 |
| 28°F | Apr 27 | Apr 12 | Mar 30 | Oct 18 | Oct 30 | Nov 15 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Markham, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 20 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Markham planting FAQ
When is the last spring frost in Markham, IL?
On average, the last spring frost in Markham is around April 23 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Markham, IL?
Expect Markham's first fall frost near October 20 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Markham in?
Markham is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Markham?
Markham has about 180 frost-free days — a moderate growing season — between the average last spring frost (April 23) and first fall frost (October 20).
When should I plant tomatoes in Markham?
For Markham, sow tomatoes indoors about February 26–March 12 and move the seedlings out around April 30, after the last spring frost.
Never miss a window in Markham
An email when it’s time to start seeds, transplant, and sow — timed to Markham’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Hazel Crest · 3 km
- Harvey · 3 km
- Midlothian · 4 km
- Country Club Hills · 5 km
- Homewood · 5 km
- Oak Forest · 5 km
- Blue Island · 6 km
- Crestwood · 7 km
Frost dates recorded at PARK FOREST, 12 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Markham, IL — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00116616. Retrieved from https://blissgarden.com/illinois/markham.