Frost dates for 97601Klamath Falls, OR
The average last spring frost in Klamath Falls is June 9 and the average first fall frost is September 18, giving a typical growing season of about 99 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 9
- Average first fall frost
- Sep 18
- Growing season
- 99 days
Safer after Jun 26 (1-in-10 risk)
Possible by Sep 4 (1-in-10 risk)
Last frost typically in 219 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) | — | — | 72 days | 100% |
| Frost / freeze (32°F) | May 22 · Jun 9 · Jun 26 | Sep 4 · Sep 18 · Oct 1 | 99 days | 100% |
| Hard freeze (28°F) | May 2 · May 21 · Jun 12 | Sep 17 · Oct 2 · Oct 17 | 132 days | 100% |
Planting calendar for Klamath Falls
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 | May 9 – Jul 15 |
| Tomatoes | Transplant outdoors | Jun 25 – May 29 |
| Peppers | Start seeds indoors | May 9 – Jun 9 |
| Peppers | Transplant outdoors | Jul 9 – Aug 9 |
| Eggplant | Start seeds indoors | May 26 – Jun 24 |
| Eggplant | Transplant outdoors | Jul 9 – Aug 9 |
| Cucumbers | Sow outdoors | Jul 9 – Jun 8 |
| Summer squash | Sow outdoors | Jun 25 – Aug 9 |
| Winter squash & pumpkins | Sow outdoors | Jul 9 – Aug 9 |
| Snap beans | Sow outdoors | Jun 25 – Jul 1 |
| Sweet corn | Sow outdoors | Jun 25 – May 29 |
| Watermelon & cantaloupe | Sow outdoors | Jul 9 – Aug 9 |
| Okra | Sow outdoors | Jul 2 – Jul 25 |
| Peas | Sow outdoors (spring) | May 9 – Jun 24 |
| Potatoes | Plant outdoors (spring) | May 9 – Jul 9 |
| Onions | Start seeds indoors (spring) | Mar 28 – Apr 24 |
| Onions | Transplant outdoors (spring) | May 26 – Jun 24 |
| Broccoli | Start seeds indoors (spring) | Apr 21 – May 25 |
| Broccoli | Transplant outdoors (spring) | May 26 – Jun 24 |
| Broccoli | Start seeds indoors (fall) | May 19 – May 29 |
| Broccoli | Transplant outdoors (fall) | Jun 18 – Jun 29 |
| Cabbage | Start seeds indoors (spring) | Apr 11 – May 9 |
| Cabbage | Transplant outdoors (spring) | May 9 – Jun 9 |
| Cabbage | Start seeds indoors (fall) | May 9 – Jun 8 |
| Cabbage | Transplant outdoors (fall) | Jun 8 – Jul 9 |
| Leaf lettuce | Sow outdoors (spring) | May 9 – Jul 25 |
| Leaf lettuce | Sow outdoors (fall) | Jun 8 – Jul 25 |
| Spinach | Sow outdoors (spring) | May 2 – Jun 15 |
| Spinach | Sow outdoors (fall) | Jun 25 – Jul 30 |
| Radishes | Sow outdoors (spring) | May 9 – Jun 29 |
| Radishes | Sow outdoors (fall) | Jun 8 – Aug 9 |
| Kale | Sow outdoors (spring) | May 26 – Jun 15 |
| Kale | Sow outdoors (fall) | Jun 1 – Jul 9 |
| Carrots | Sow outdoors (spring) | Jun 9 – Jul 25 |
| Carrots | Sow outdoors (fall) | May 9 – Jun 24 |
| Garlic | Plant outdoors (fall) | Sep 8 – Oct 9 |
Where these dates come from
ZIP code 97601 is matched to the NOAA station Klamath Falls Intl Ap, OR, 18 km away, at 4,084 ft elevation (60 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Klamath Falls Intl Ap, OR (used) | 4,084 ft | Jun 9 | Sep 18 |
| Keno, OR | 4,128 ft | Jun 5 | Sep 20 |
| Tulelake, CA | 4,038 ft | Jun 6 | Sep 14 |
| Howard Prairie Dam, OR | 4,567 ft | Jun 8 | Sep 24 |
Frost dates near Klamath Falls
- Klamath Falls, OR 97602 · last Jun 9, first Sep 18
- Midland, OR 97634 · last Jun 9, first Sep 18
- Keno, OR 97627 · last Jun 9, first Sep 18
- Dairy, OR 97625 · last Jun 9, first Sep 18
- Chiloquin, OR 97624 · last —, first —
- Merrill, OR 97633 · last Jun 6, first Sep 14
- Sprague River, OR 97639 · last Jun 9, first Sep 18
- Bonanza, OR 97623 · last May 31, first Sep 21
Frequently asked questions
- When is the last frost in Klamath Falls, OR?
- For ZIP code 97601, the average last spring frost (32°F) is June 9, based on NOAA 1991-2020 climate normals for the Klamath Falls Intl Ap, OR weather station. There is a 1-in-10 chance of a frost after June 26.
- When is the first frost in Klamath Falls, OR?
- The average first fall frost (32°F) is September 18. There is a 1-in-10 chance of frost by September 4, so tender plants are at risk from that point on.
- How long is the growing season in 97601?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 99 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.