When to plant in Orono, ME
USDA Zone 5aOrono, Maine frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
In zone 5a, Orono gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average first fall frost in Orono is now 5 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
ORONO · 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 Orono’s own odds, recorded at ORONO.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 31 | May 14 | May 2 | Sep 13 | Sep 28 | Oct 9 |
| 32°F | May 14 | May 1 | Apr 22 | Sep 24 | Oct 6 | Oct 22 |
| 28°F | May 1 | Apr 20 | Apr 9 | Oct 3 | Oct 20 | Nov 5 |
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 Orono, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 14 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.
Orono planting FAQ
When is the last spring frost in Orono, ME?
Plan for the last spring frost in Orono around May 1 (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 Orono, ME?
Expect Orono's first fall frost near October 6 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Orono in?
Orono is in USDA hardiness zone 5a. In zone 5a, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Orono?
Orono has about 158 frost-free days — a moderate growing season — between the average last spring frost (May 1) and first fall frost (October 6).
When should I plant tomatoes in Orono?
For Orono, sow tomatoes indoors about March 6–March 20 and move the seedlings out around May 8, after the last spring frost.
Never miss a window in Orono
An email when it’s time to start seeds, transplant, and sow — timed to Orono’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at ORONO, 3 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 Orono, ME — Frost Dates & Zone 5a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00176430. Retrieved from https://blissgarden.com/maine/orono.