Frost dates for 64620Altamont, MO
The average last spring frost in Altamont is April 19 and the average first fall frost is October 21, giving a typical growing season of about 184 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 19
- Average first fall frost
- Oct 21
- Growing season
- 184 days
Safer after May 4 (1-in-10 risk)
Possible by Oct 6 (1-in-10 risk)
Last frost typically in 167 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 15 · Apr 30 · May 14 | Sep 25 · Oct 9 · Oct 23 | 163 days | 100% |
| Frost / freeze (32°F) | Apr 5 · Apr 19 · May 4 | Oct 6 · Oct 21 · Nov 1 | 184 days | 100% |
| Hard freeze (28°F) | Mar 22 · Apr 7 · Apr 23 | Oct 16 · Oct 30 · Nov 11 | 203 days | 100% |
Planting calendar for Altamont
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 – Jul 1 |
| 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 11 |
| Summer squash | Sow outdoors | May 5 – Jun 19 |
| Winter squash & pumpkins | Sow outdoors | May 19 – Jun 19 |
| Snap beans | Sow outdoors | May 5 – Aug 3 |
| Sweet corn | Sow outdoors | May 5 – Jul 1 |
| 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 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 19 – Mar 19 |
| Cabbage | Transplant outdoors (spring) | Mar 19 – Apr 19 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 19 – Jun 4 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 12 – Apr 25 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 19 – May 9 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 5 – Apr 25 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 19 – Jun 4 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 64620 is matched to the NOAA station Gallatin 1W, MO, 10.3 km away, at 921 ft elevation (57 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Gallatin 1W, MO (used) | 921 ft | Apr 19 | Oct 21 |
| Hamilton 2W, MO | 900 ft | Apr 23 | Oct 17 |
| Cameron, MO | 1,010 ft | Apr 15 | Oct 24 |
| Amity 4 Ne, MO | 974 ft | Apr 19 | Oct 19 |
Frost dates near Altamont
- Winston, MO 64689 · last Apr 19, first Oct 19
- Gallatin, MO 64640 · last Apr 19, first Oct 21
- Kidder, MO 64649 · last Apr 23, first Oct 17
- Weatherby, MO 64497 · last Apr 19, first Oct 19
- Jameson, MO 64647 · last Apr 19, first Oct 21
- Pattonsburg, MO 64670 · last Apr 19, first Oct 21
- Hamilton, MO 64644 · last Apr 23, first Oct 17
- Cameron, MO 64429 · last Apr 15, first Oct 24
Frequently asked questions
- When is the last frost in Altamont, MO?
- For ZIP code 64620, the average last spring frost (32°F) is April 19, based on NOAA 1991-2020 climate normals for the Gallatin 1W, MO weather station. There is a 1-in-10 chance of a frost after May 4.
- When is the first frost in Altamont, MO?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 6, so tender plants are at risk from that point on.
- How long is the growing season in 64620?
- 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.