When to plant in Mason, OH
USDA Zone 6bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Mason, Ohio — all computed from Mason's nearest NOAA weather station.
These dates come from a station roughly 20 km away, the closest with full normals; terrain around Mason (elevation, water, pavement) can move your real frost dates a few days either way. Zone 6b means Mason sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
HAMILTON BUTLER CO RGNL AP · 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 Mason’s own odds, recorded at HAMILTON BUTLER CO RGNL AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 19 | May 2 | Apr 18 | Sep 25 | Oct 7 | Oct 20 |
| 32°F | May 10 | Apr 22 | Apr 6 | Oct 5 | Oct 18 | Oct 29 |
| 28°F | Apr 28 | Apr 8 | Mar 26 | Oct 15 | Oct 27 | Nov 8 |
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 Mason, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 22 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.
Mason planting FAQ
When is the last spring frost in Mason, OH?
Plan for the last spring frost in Mason around April 22 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Mason, OH?
Expect Mason's first fall frost near October 18 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Mason in?
Mason is in USDA hardiness zone 6b. In zone 6b, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Mason?
There are roughly 179 frost-free days in Mason (a moderate growing season), running from the average last frost around April 22 to the first fall frost near October 18.
When should I plant tomatoes in Mason?
In Mason, start tomato seeds indoors around February 25–March 11, then transplant seedlings outdoors around April 29 once the danger of frost has passed.
Never miss a window in Mason
An email when it’s time to start seeds, transplant, and sow — timed to Mason’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Lebanon · 10 km
- Loveland · 11 km
- Monroe · 11 km
- Montgomery · 13 km
- Sharonville · 13 km
- Blue Ash · 15 km
- Middletown · 17 km
- Springdale · 17 km
Frost dates recorded at HAMILTON BUTLER CO RGNL AP, 20 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 Mason, OH — Frost Dates & Zone 6b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00053855. Retrieved from https://blissgarden.com/ohio/mason.