Frost dates for 45875Ottawa, OH
The average last spring frost in Ottawa is April 23 and the average first fall frost is October 22, giving a typical growing season of about 180 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 23
- Average first fall frost
- Oct 22
- Growing season
- 180 days
Safer after May 9 (1-in-10 risk)
Possible by Oct 6 (1-in-10 risk)
Last frost typically in 173 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 19 · May 3 · May 18 | Sep 26 · Oct 10 · Oct 23 | 158 days | 100% |
| Frost / freeze (32°F) | Apr 10 · Apr 23 · May 9 | Oct 6 · Oct 22 · Nov 4 | 180 days | 100% |
| Hard freeze (28°F) | Mar 29 · Apr 14 · Apr 29 | Oct 20 · Nov 2 · Nov 16 | 203 days | 100% |
Planting calendar for Ottawa
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 23 – May 29 |
| Tomatoes | Transplant outdoors | May 9 – Jul 2 |
| Peppers | Start seeds indoors | Mar 23 – Apr 23 |
| Peppers | Transplant outdoors | May 23 – Jun 23 |
| Eggplant | Start seeds indoors | Apr 9 – May 8 |
| Eggplant | Transplant outdoors | May 23 – Jun 23 |
| Cucumbers | Sow outdoors | May 23 – Jul 12 |
| Summer squash | Sow outdoors | May 9 – Jun 23 |
| Winter squash & pumpkins | Sow outdoors | May 23 – Jun 23 |
| Snap beans | Sow outdoors | May 9 – Aug 4 |
| Sweet corn | Sow outdoors | May 9 – Jul 2 |
| Watermelon & cantaloupe | Sow outdoors | May 23 – Jun 23 |
| Okra | Sow outdoors | May 16 – Jun 8 |
| Peas | Sow outdoors (spring) | Mar 23 – May 8 |
| Potatoes | Plant outdoors (spring) | Mar 23 – May 23 |
| Onions | Start seeds indoors (spring) | Feb 9 – Mar 8 |
| Onions | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (spring) | Mar 5 – Apr 8 |
| Broccoli | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (fall) | Jun 22 – Jul 2 |
| Broccoli | Transplant outdoors (fall) | Jul 22 – Aug 2 |
| Cabbage | Start seeds indoors (spring) | Feb 23 – Mar 23 |
| Cabbage | Transplant outdoors (spring) | Mar 23 – Apr 23 |
| Cabbage | Start seeds indoors (fall) | Jun 12 – Jul 12 |
| Cabbage | Transplant outdoors (fall) | Jul 12 – Aug 12 |
| Leaf lettuce | Sow outdoors (spring) | Mar 23 – Jun 8 |
| Leaf lettuce | Sow outdoors (fall) | Jul 12 – Aug 28 |
| Spinach | Sow outdoors (spring) | Mar 16 – Apr 29 |
| Spinach | Sow outdoors (fall) | Jul 29 – Sep 2 |
| Radishes | Sow outdoors (spring) | Mar 23 – May 13 |
| Radishes | Sow outdoors (fall) | Jul 12 – Sep 12 |
| Kale | Sow outdoors (spring) | Apr 9 – Apr 29 |
| Kale | Sow outdoors (fall) | Jul 5 – Aug 12 |
| Carrots | Sow outdoors (spring) | Apr 23 – Jun 8 |
| Carrots | Sow outdoors (fall) | Jun 12 – Jul 28 |
| Garlic | Plant outdoors (fall) | Oct 12 – Nov 12 |
Where these dates come from
ZIP code 45875 is matched to the NOAA station Pandora, OH, 10.9 km away, at 770 ft elevation (42 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Pandora, OH (used) | 770 ft | Apr 23 | Oct 22 |
| Findlay Ap, OH | 800 ft | Apr 19 | Oct 23 |
| Hoytville 2 Ne, OH | 700 ft | Apr 24 | Oct 21 |
| Findlay Wpcc, OH | 768 ft | Apr 22 | Oct 24 |
Frost dates near Ottawa
- Glandorf, OH 45848 · last Apr 23, first Oct 22
- Leipsic, OH 45856 · last Apr 23, first Oct 22
- Pandora, OH 45877 · last Apr 23, first Oct 22
- Miller City, OH 45864 · last Apr 23, first Oct 22
- Columbus Grove, OH 45830 · last Apr 23, first Oct 22
- Kalida, OH 45853 · last Apr 23, first Oct 22
- Belmore, OH 45815 · last Apr 24, first Oct 21
- Vaughnsville, OH 45893 · last Apr 23, first Oct 22
Frequently asked questions
- When is the last frost in Ottawa, OH?
- For ZIP code 45875, the average last spring frost (32°F) is April 23, based on NOAA 1991-2020 climate normals for the Pandora, OH weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Ottawa, OH?
- The average first fall frost (32°F) is October 22. There is a 1-in-10 chance of frost by October 6, so tender plants are at risk from that point on.
- How long is the growing season in 45875?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 180 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.