Frost dates for 64646Humphreys, MO
The average last spring frost in Humphreys is April 16 and the average first fall frost is October 20, giving a typical growing season of about 184 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 16
- Average first fall frost
- Oct 20
- Growing season
- 184 days
Safer after Apr 29 (1-in-10 risk)
Possible by Oct 5 (1-in-10 risk)
Last frost typically in 164 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 27 · May 9 | Sep 26 · Oct 11 · Oct 23 | 165 days | 100% |
| Frost / freeze (32°F) | Apr 3 · Apr 16 · Apr 29 | Oct 5 · Oct 20 · Nov 1 | 184 days | 100% |
| Hard freeze (28°F) | Mar 22 · Apr 6 · Apr 21 | Oct 16 · Oct 29 · Nov 11 | 204 days | 100% |
Planting calendar for Humphreys
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 16 – May 22 |
| Tomatoes | Transplant outdoors | May 2 – Jun 30 |
| Peppers | Start seeds indoors | Mar 16 – Apr 16 |
| Peppers | Transplant outdoors | May 16 – Jun 16 |
| Eggplant | Start seeds indoors | Apr 2 – May 1 |
| Eggplant | Transplant outdoors | May 16 – Jun 16 |
| Cucumbers | Sow outdoors | May 16 – Jul 10 |
| Summer squash | Sow outdoors | May 2 – Jun 16 |
| Winter squash & pumpkins | Sow outdoors | May 16 – Jun 16 |
| Snap beans | Sow outdoors | May 2 – Aug 2 |
| Sweet corn | Sow outdoors | May 2 – Jun 30 |
| Watermelon & cantaloupe | Sow outdoors | May 16 – Jun 16 |
| Okra | Sow outdoors | May 9 – Jun 1 |
| Peas | Sow outdoors (spring) | Mar 16 – May 1 |
| Potatoes | Plant outdoors (spring) | Mar 16 – May 16 |
| Onions | Start seeds indoors (spring) | Feb 2 – Mar 1 |
| Onions | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (spring) | Feb 26 – Apr 1 |
| Broccoli | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (fall) | Jun 20 – Jun 30 |
| Broccoli | Transplant outdoors (fall) | Jul 20 – Jul 31 |
| Cabbage | Start seeds indoors (spring) | Feb 16 – Mar 16 |
| Cabbage | Transplant outdoors (spring) | Mar 16 – Apr 16 |
| Cabbage | Start seeds indoors (fall) | Jun 10 – Jul 10 |
| Cabbage | Transplant outdoors (fall) | Jul 10 – Aug 10 |
| Leaf lettuce | Sow outdoors (spring) | Mar 16 – Jun 1 |
| Leaf lettuce | Sow outdoors (fall) | Jul 10 – Aug 26 |
| Spinach | Sow outdoors (spring) | Mar 9 – Apr 22 |
| Spinach | Sow outdoors (fall) | Jul 27 – Aug 31 |
| Radishes | Sow outdoors (spring) | Mar 16 – May 6 |
| Radishes | Sow outdoors (fall) | Jul 10 – Sep 10 |
| Kale | Sow outdoors (spring) | Apr 2 – Apr 22 |
| Kale | Sow outdoors (fall) | Jul 3 – Aug 10 |
| Carrots | Sow outdoors (spring) | Apr 16 – Jun 1 |
| Carrots | Sow outdoors (fall) | Jun 10 – Jul 26 |
| Garlic | Plant outdoors (fall) | Oct 10 – Nov 10 |
Where these dates come from
ZIP code 64646 is matched to the NOAA station Trenton, MO, 26.4 km away, at 837 ft elevation (92 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Trenton, MO (used) | 837 ft | Apr 16 | Oct 20 |
| Chillicothe 22 Ene, MO | 833 ft | Apr 15 | Oct 20 |
| Linneus 3Se, MO | 814 ft | Apr 16 | Oct 20 |
| Spickard 7 W, MO | 875 ft | Apr 20 | Oct 16 |
Frost dates near Humphreys
- Galt, MO 64641 · last Apr 16, first Oct 20
- Browning, MO 64630 · last Apr 15, first Oct 20
- Milan, MO 63556 · last Apr 15, first Oct 20
- Laredo, MO 64652 · last Apr 16, first Oct 20
- Purdin, MO 64674 · last Apr 15, first Oct 20
- Harris, MO 64645 · last Apr 25, first Oct 15
- Linneus, MO 64653 · last Apr 15, first Oct 20
- Trenton, MO 64683 · last Apr 16, first Oct 20
Frequently asked questions
- When is the last frost in Humphreys, MO?
- For ZIP code 64646, the average last spring frost (32°F) is April 16, based on NOAA 1991-2020 climate normals for the Trenton, MO weather station. There is a 1-in-10 chance of a frost after April 29.
- When is the first frost in Humphreys, MO?
- The average first fall frost (32°F) is October 20. 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 64646?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 184 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.