Frost dates for 64494Union Star, MO
The average last spring frost in Union Star is April 19 and the average first fall frost is October 19, giving a typical growing season of about 180 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 19
- Average first fall frost
- Oct 19
- Growing season
- 180 days
Safer after May 4 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 174 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 16 · Apr 30 · May 15 | Sep 24 · Oct 8 · Oct 22 | 160 days | 100% |
| Frost / freeze (32°F) | Apr 4 · Apr 19 · May 4 | Oct 2 · Oct 19 · Oct 30 | 180 days | 100% |
| Hard freeze (28°F) | Mar 24 · Apr 8 · Apr 23 | Oct 15 · Oct 29 · Nov 10 | 201 days | 100% |
Planting calendar for Union Star
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 19 – May 25 |
| Tomatoes | Transplant outdoors | May 5 – Jun 29 |
| Peppers | Start seeds indoors | Mar 19 – Apr 19 |
| Peppers | Transplant outdoors | May 19 – Jun 19 |
| Eggplant | Start seeds indoors | Apr 5 – May 4 |
| Eggplant | Transplant outdoors | May 19 – Jun 19 |
| Cucumbers | Sow outdoors | May 19 – Jul 9 |
| Summer squash | Sow outdoors | May 5 – Jun 19 |
| Winter squash & pumpkins | Sow outdoors | May 19 – Jun 19 |
| Snap beans | Sow outdoors | May 5 – Aug 1 |
| Sweet corn | Sow outdoors | May 5 – Jun 29 |
| Watermelon & cantaloupe | Sow outdoors | May 19 – Jun 19 |
| Okra | Sow outdoors | May 12 – Jun 4 |
| Peas | Sow outdoors (spring) | Mar 19 – May 4 |
| Potatoes | Plant outdoors (spring) | Mar 19 – May 19 |
| Onions | Start seeds indoors (spring) | Feb 5 – Mar 4 |
| Onions | Transplant outdoors (spring) | Apr 5 – May 4 |
| Broccoli | Start seeds indoors (spring) | Mar 1 – Apr 4 |
| Broccoli | Transplant outdoors (spring) | Apr 5 – May 4 |
| Broccoli | Start seeds indoors (fall) | Jun 19 – Jun 29 |
| Broccoli | Transplant outdoors (fall) | Jul 19 – Jul 30 |
| Cabbage | Start seeds indoors (spring) | Feb 19 – Mar 19 |
| Cabbage | Transplant outdoors (spring) | Mar 19 – Apr 19 |
| Cabbage | Start seeds indoors (fall) | Jun 9 – Jul 9 |
| Cabbage | Transplant outdoors (fall) | Jul 9 – Aug 9 |
| Leaf lettuce | Sow outdoors (spring) | Mar 19 – Jun 4 |
| Leaf lettuce | Sow outdoors (fall) | Jul 9 – Aug 25 |
| Spinach | Sow outdoors (spring) | Mar 12 – Apr 25 |
| Spinach | Sow outdoors (fall) | Jul 26 – Aug 30 |
| Radishes | Sow outdoors (spring) | Mar 19 – May 9 |
| Radishes | Sow outdoors (fall) | Jul 9 – Sep 9 |
| Kale | Sow outdoors (spring) | Apr 5 – Apr 25 |
| Kale | Sow outdoors (fall) | Jul 2 – Aug 9 |
| Carrots | Sow outdoors (spring) | Apr 19 – Jun 4 |
| Carrots | Sow outdoors (fall) | Jun 9 – Jul 25 |
| Garlic | Plant outdoors (fall) | Oct 9 – Nov 9 |
Where these dates come from
ZIP code 64494 is matched to the NOAA station Amity 4 Ne, MO, 21.3 km away, at 974 ft elevation (43 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Amity 4 Ne, MO (used) | 974 ft | Apr 19 | Oct 19 |
| Cosby 2W, MO | 910 ft | Apr 17 | Oct 19 |
| Conception, MO | 1,108 ft | Apr 17 | Oct 20 |
| Albany, MO | 875 ft | Apr 17 | Oct 21 |
Frost dates near Union Star
- Helena, MO 64459 · last Apr 19, first Oct 19
- King City, MO 64463 · last Apr 17, first Oct 20
- Amity, MO 64422 · last Apr 19, first Oct 19
- Rea, MO 64480 · last Apr 17, first Oct 20
- Cosby, MO 64436 · last Apr 17, first Oct 19
- Clarksdale, MO 64430 · last Apr 19, first Oct 19
- Maysville, MO 64469 · last Apr 19, first Oct 19
- Stewartsville, MO 64490 · last Apr 19, first Oct 19
Frequently asked questions
- When is the last frost in Union Star, MO?
- For ZIP code 64494, the average last spring frost (32°F) is April 19, based on NOAA 1991-2020 climate normals for the Amity 4 Ne, MO weather station. There is a 1-in-10 chance of a frost after May 4.
- When is the first frost in Union Star, MO?
- The average first fall frost (32°F) is October 19. There is a 1-in-10 chance of frost by October 2, so tender plants are at risk from that point on.
- How long is the growing season in 64494?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 180 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.