Frost dates for 66939Courtland, KS
The average last spring frost in Courtland is April 17 and the average first fall frost is October 21, giving a typical growing season of about 187 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 17
- Average first fall frost
- Oct 21
- Growing season
- 187 days
Safer after Apr 29 (1-in-10 risk)
Possible by Oct 5 (1-in-10 risk)
Last frost typically in 166 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 13 · Apr 26 · May 7 | Sep 27 · Oct 12 · Oct 25 | 169 days | 100% |
| Frost / freeze (32°F) | Apr 2 · Apr 17 · Apr 29 | Oct 5 · Oct 21 · Nov 4 | 187 days | 100% |
| Hard freeze (28°F) | Mar 21 · Apr 8 · Apr 22 | Oct 16 · Nov 1 · Nov 16 | 206 days | 100% |
Planting calendar for Courtland
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 17 – May 23 |
| Tomatoes | Transplant outdoors | May 3 – Jul 1 |
| Peppers | Start seeds indoors | Mar 17 – Apr 17 |
| Peppers | Transplant outdoors | May 17 – Jun 17 |
| Eggplant | Start seeds indoors | Apr 3 – May 2 |
| Eggplant | Transplant outdoors | May 17 – Jun 17 |
| Cucumbers | Sow outdoors | May 17 – Jul 11 |
| Summer squash | Sow outdoors | May 3 – Jun 17 |
| Winter squash & pumpkins | Sow outdoors | May 17 – Jun 17 |
| Snap beans | Sow outdoors | May 3 – Aug 3 |
| Sweet corn | Sow outdoors | May 3 – Jul 1 |
| Watermelon & cantaloupe | Sow outdoors | May 17 – Jun 17 |
| Okra | Sow outdoors | May 10 – Jun 2 |
| Peas | Sow outdoors (spring) | Mar 17 – May 2 |
| Potatoes | Plant outdoors (spring) | Mar 17 – May 17 |
| Onions | Start seeds indoors (spring) | Feb 3 – Mar 2 |
| Onions | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (spring) | Feb 27 – Apr 2 |
| Broccoli | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (fall) | Jun 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 17 – Mar 17 |
| Cabbage | Transplant outdoors (spring) | Mar 17 – Apr 17 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 17 – Jun 2 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 10 – Apr 23 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 17 – May 7 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 3 – Apr 23 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 66939 is matched to the NOAA station Courtland, KS, 0.7 km away, at 1,500 ft elevation (1 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Courtland, KS (used) | 1,500 ft | Apr 17 | Oct 21 |
| Lovewell Dam, KS | 1,602 ft | Apr 20 | Oct 19 |
| Belleville, KS | 1,530 ft | Apr 22 | Oct 17 |
| Mankato, KS | 1,750 ft | Apr 30 | Oct 14 |
Frost dates near Courtland
- Formoso, KS 66942 · last Apr 17, first Oct 21
- Scandia, KS 66966 · last Apr 17, first Oct 21
- Republic, KS 66964 · last Apr 17, first Oct 21
- Jamestown, KS 66948 · last Apr 21, first Oct 19
- Webber, KS 66970 · last Apr 20, first Oct 19
- Norway, KS 66961 · last Apr 22, first Oct 17
- Belleville, KS 66935 · last Apr 22, first Oct 17
- Randall, KS 66963 · last Apr 17, first Oct 21
Frequently asked questions
- When is the last frost in Courtland, KS?
- For ZIP code 66939, the average last spring frost (32°F) is April 17, based on NOAA 1991-2020 climate normals for the Courtland, KS weather station. There is a 1-in-10 chance of a frost after April 29.
- When is the first frost in Courtland, KS?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 5, so tender plants are at risk from that point on.
- How long is the growing season in 66939?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 187 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.