Frost dates for 68634Duncan, NE
The average last spring frost in Duncan is April 21 and the average first fall frost is October 15, giving a typical growing season of about 174 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 21
- Average first fall frost
- Oct 15
- Growing season
- 174 days
Safer after May 5 (1-in-10 risk)
Possible by Sep 30 (1-in-10 risk)
Last frost typically in 176 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 17 · May 1 · May 14 | Sep 23 · Oct 6 · Oct 18 | 156 days | 100% |
| Frost / freeze (32°F) | Apr 7 · Apr 21 · May 5 | Sep 30 · Oct 15 · Oct 27 | 174 days | 100% |
| Hard freeze (28°F) | Mar 30 · Apr 11 · Apr 26 | Oct 9 · Oct 24 · Nov 5 | 193 days | 100% |
Planting calendar for Duncan
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 21 – May 27 |
| Tomatoes | Transplant outdoors | May 7 – Jun 25 |
| Peppers | Start seeds indoors | Mar 21 – Apr 21 |
| Peppers | Transplant outdoors | May 21 – Jun 21 |
| Eggplant | Start seeds indoors | Apr 7 – May 6 |
| Eggplant | Transplant outdoors | May 21 – Jun 21 |
| Cucumbers | Sow outdoors | May 21 – Jul 5 |
| Summer squash | Sow outdoors | May 7 – Jun 21 |
| Winter squash & pumpkins | Sow outdoors | May 21 – Jun 21 |
| Snap beans | Sow outdoors | May 7 – Jul 28 |
| Sweet corn | Sow outdoors | May 7 – Jun 25 |
| Watermelon & cantaloupe | Sow outdoors | May 21 – Jun 21 |
| Okra | Sow outdoors | May 14 – Jun 6 |
| Peas | Sow outdoors (spring) | Mar 21 – May 6 |
| Potatoes | Plant outdoors (spring) | Mar 21 – May 21 |
| Onions | Start seeds indoors (spring) | Feb 7 – Mar 6 |
| Onions | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (spring) | Mar 3 – Apr 6 |
| Broccoli | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (fall) | Jun 15 – Jun 25 |
| Broccoli | Transplant outdoors (fall) | Jul 15 – Jul 26 |
| Cabbage | Start seeds indoors (spring) | Feb 21 – Mar 21 |
| Cabbage | Transplant outdoors (spring) | Mar 21 – Apr 21 |
| Cabbage | Start seeds indoors (fall) | Jun 5 – Jul 5 |
| Cabbage | Transplant outdoors (fall) | Jul 5 – Aug 5 |
| Leaf lettuce | Sow outdoors (spring) | Mar 21 – Jun 6 |
| Leaf lettuce | Sow outdoors (fall) | Jul 5 – Aug 21 |
| Spinach | Sow outdoors (spring) | Mar 14 – Apr 27 |
| Spinach | Sow outdoors (fall) | Jul 22 – Aug 26 |
| Radishes | Sow outdoors (spring) | Mar 21 – May 11 |
| Radishes | Sow outdoors (fall) | Jul 5 – Sep 5 |
| Kale | Sow outdoors (spring) | Apr 7 – Apr 27 |
| Kale | Sow outdoors (fall) | Jun 28 – Aug 5 |
| Carrots | Sow outdoors (spring) | Apr 21 – Jun 6 |
| Carrots | Sow outdoors (fall) | Jun 5 – Jul 21 |
| Garlic | Plant outdoors (fall) | Oct 5 – Nov 5 |
Where these dates come from
ZIP code 68634 is matched to the NOAA station Columbus 3 Ne, NE, 16.2 km away, at 1,450 ft elevation (43 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Columbus 3 Ne, NE (used) | 1,450 ft | Apr 21 | Oct 15 |
| Osceola, NE | 1,662 ft | Apr 25 | Oct 14 |
| Genoa 2 W, NE | 1,590 ft | Apr 30 | Oct 5 |
| David City, NE | 1,610 ft | Apr 26 | Oct 11 |
Frost dates near Duncan
- Columbus, NE 68601 · last Apr 21, first Oct 15
- Monroe, NE 68647 · last Apr 30, first Oct 5
- Silver Creek, NE 68663 · last Apr 30, first Oct 5
- Platte Center, NE 68653 · last Apr 21, first Oct 15
- Bellwood, NE 68624 · last Apr 21, first Oct 15
- Osceola, NE 68651 · last Apr 25, first Oct 14
- Shelby, NE 68662 · last Apr 25, first Oct 14
- Genoa, NE 68640 · last Apr 30, first Oct 5
Frequently asked questions
- When is the last frost in Duncan, NE?
- For ZIP code 68634, the average last spring frost (32°F) is April 21, based on NOAA 1991-2020 climate normals for the Columbus 3 Ne, NE weather station. There is a 1-in-10 chance of a frost after May 5.
- When is the first frost in Duncan, NE?
- The average first fall frost (32°F) is October 15. There is a 1-in-10 chance of frost by September 30, so tender plants are at risk from that point on.
- How long is the growing season in 68634?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 174 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.