Frost dates for 97603Klamath 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 97603 is matched to the NOAA station Klamath Falls Intl Ap, OR, 5 km away, at 4,084 ft elevation (40 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 |
| Gerber Dam, OR | 4,870 ft | May 31 | Sep 21 |
Frost dates near Klamath Falls
- Klamath Falls, OR 97602 · last Jun 9, first Sep 18
- Midland, OR 97634 · last Jun 9, first Sep 18
- Dairy, OR 97625 · last Jun 9, first Sep 18
- Keno, OR 97627 · last Jun 9, first Sep 18
- Merrill, OR 97633 · last Jun 6, first Sep 14
- Malin, OR 97632 · last Jun 6, first Sep 14
- Bonanza, OR 97623 · last May 31, first Sep 21
- Dorris, CA 96023 · last Jun 9, first Sep 18
Frequently asked questions
- When is the last frost in Klamath Falls, OR?
- For ZIP code 97603, 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 97603?
- 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.