Frost dates for 97420Coos Bay, OR
The average last spring frost in Coos Bay is March 28 and the average first fall frost is November 6, giving a typical growing season of about 225 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 28
- Average first fall frost
- Nov 6
- Growing season
- 225 days
Safer after Apr 27 (1-in-10 risk)
Possible by Oct 17 (1-in-10 risk)
First frost typically in 4 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 7 · Apr 30 · May 19 | Sep 30 · Oct 18 · Nov 9 | 170 days | 100% |
| Frost / freeze (32°F) | Feb 22 · Mar 28 · Apr 27 | Oct 17 · Nov 6 · Dec 6 | 225 days | 100% |
| Hard freeze (28°F) | Dec 28 · Feb 16 · Mar 22 | Nov 2 · Dec 2 · Jan 13 | 299 days | 96% |
Planting calendar for Coos Bay
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 | Feb 25 – May 3 |
| Tomatoes | Transplant outdoors | Apr 13 – Jul 17 |
| Peppers | Start seeds indoors | Feb 25 – Mar 28 |
| Peppers | Transplant outdoors | Apr 27 – May 28 |
| Eggplant | Start seeds indoors | Mar 14 – Apr 12 |
| Eggplant | Transplant outdoors | Apr 27 – May 28 |
| Cucumbers | Sow outdoors | Apr 27 – Jul 27 |
| Summer squash | Sow outdoors | Apr 13 – May 28 |
| Winter squash & pumpkins | Sow outdoors | Apr 27 – May 28 |
| Snap beans | Sow outdoors | Apr 13 – Aug 19 |
| Sweet corn | Sow outdoors | Apr 13 – Jul 17 |
| Watermelon & cantaloupe | Sow outdoors | Apr 27 – May 28 |
| Okra | Sow outdoors | Apr 20 – May 13 |
| Peas | Sow outdoors (spring) | Feb 25 – Apr 12 |
| Potatoes | Plant outdoors (spring) | Feb 25 – Apr 27 |
| Onions | Start seeds indoors (spring) | Jan 14 – Feb 10 |
| Onions | Transplant outdoors (spring) | Mar 14 – Apr 12 |
| Broccoli | Start seeds indoors (spring) | Feb 7 – Mar 13 |
| Broccoli | Transplant outdoors (spring) | Mar 14 – Apr 12 |
| Broccoli | Start seeds indoors (fall) | Jul 7 – Jul 17 |
| Broccoli | Transplant outdoors (fall) | Aug 6 – Aug 17 |
| Cabbage | Start seeds indoors (spring) | Jan 28 – Feb 25 |
| Cabbage | Transplant outdoors (spring) | Feb 25 – Mar 28 |
| Cabbage | Start seeds indoors (fall) | Jun 27 – Jul 27 |
| Cabbage | Transplant outdoors (fall) | Jul 27 – Aug 27 |
| Leaf lettuce | Sow outdoors (spring) | Feb 25 – May 13 |
| Leaf lettuce | Sow outdoors (fall) | Jul 27 – Sep 12 |
| Spinach | Sow outdoors (spring) | Feb 18 – Apr 3 |
| Spinach | Sow outdoors (fall) | Aug 13 – Sep 17 |
| Radishes | Sow outdoors (spring) | Feb 25 – Apr 17 |
| Radishes | Sow outdoors (fall) | Jul 27 – Sep 27 |
| Kale | Sow outdoors (spring) | Mar 14 – Apr 3 |
| Kale | Sow outdoors (fall) | Jul 20 – Aug 27 |
| Carrots | Sow outdoors (spring) | Mar 28 – May 13 |
| Carrots | Sow outdoors (fall) | Jun 27 – Aug 12 |
| Garlic | Plant outdoors (fall) | Oct 27 – Nov 27 |
Where these dates come from
ZIP code 97420 is matched to the NOAA station Coquille City, OR, 3.1 km away, at 23 ft elevation (144 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Coquille City, OR (used) | 23 ft | Mar 28 | Nov 6 |
| Coos Bay 8 Sw, OR | 12 ft | Apr 15 | Oct 31 |
| Bandon 2 Nne, OR | 23 ft | Mar 9 | Nov 27 |
| North Bend Rgnl Ap, OR | 17 ft | Feb 21 | Dec 9 |
Frost dates near Coos Bay
- Coquille, OR 97423 · last Mar 28, first Nov 6
- Myrtle Point, OR 97458 · last Mar 21, first Nov 14
- Bandon, OR 97411 · last Mar 9, first Nov 27
- North Bend, OR 97459 · last Feb 21, first Dec 9
- Broadbent, OR 97414 · last Mar 21, first Nov 14
- Allegany, OR 97407 · last Feb 21, first Dec 9
- Powers, OR 97466 · last Mar 21, first Nov 14
- Langlois, OR 97450 · last Mar 16, first Nov 29
Frequently asked questions
- When is the last frost in Coos Bay, OR?
- For ZIP code 97420, the average last spring frost (32°F) is March 28, based on NOAA 1991-2020 climate normals for the Coquille City, OR weather station. There is a 1-in-10 chance of a frost after April 27.
- When is the first frost in Coos Bay, OR?
- The average first fall frost (32°F) is November 6. There is a 1-in-10 chance of frost by October 17, so tender plants are at risk from that point on.
- How long is the growing season in 97420?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 225 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.