Frost dates for 82450Wapiti, WY
The average last spring frost in Wapiti is May 27 and the average first fall frost is September 25, giving a typical growing season of about 121 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 27
- Average first fall frost
- Sep 25
- Growing season
- 121 days
Safer after Jun 12 (1-in-10 risk)
Possible by Sep 7 (1-in-10 risk)
Last frost typically in 212 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) | May 28 · Jun 12 · Jun 26 | Aug 27 · Sep 13 · Sep 30 | 93 days | 100% |
| Frost / freeze (32°F) | May 11 · May 27 · Jun 12 | Sep 7 · Sep 25 · Oct 9 | 121 days | 100% |
| Hard freeze (28°F) | Apr 27 · May 11 · May 26 | Sep 20 · Oct 5 · Oct 23 | 146 days | 100% |
Planting calendar for Wapiti
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 | Apr 26 – Jul 2 |
| Tomatoes | Transplant outdoors | Jun 12 – Jun 5 |
| Peppers | Start seeds indoors | Apr 26 – May 27 |
| Peppers | Transplant outdoors | Jun 26 – Jul 27 |
| Eggplant | Start seeds indoors | May 13 – Jun 11 |
| Eggplant | Transplant outdoors | Jun 26 – Jul 27 |
| Cucumbers | Sow outdoors | Jun 26 – Jun 15 |
| Summer squash | Sow outdoors | Jun 12 – Jul 27 |
| Winter squash & pumpkins | Sow outdoors | Jun 26 – Jul 27 |
| Snap beans | Sow outdoors | Jun 12 – Jul 8 |
| Sweet corn | Sow outdoors | Jun 12 – Jun 5 |
| Watermelon & cantaloupe | Sow outdoors | Jun 26 – Jul 27 |
| Okra | Sow outdoors | Jun 19 – Jul 12 |
| Peas | Sow outdoors (spring) | Apr 26 – Jun 11 |
| Potatoes | Plant outdoors (spring) | Apr 26 – Jun 26 |
| Onions | Start seeds indoors (spring) | Mar 15 – Apr 11 |
| Onions | Transplant outdoors (spring) | May 13 – Jun 11 |
| Broccoli | Start seeds indoors (spring) | Apr 8 – May 12 |
| Broccoli | Transplant outdoors (spring) | May 13 – Jun 11 |
| Broccoli | Start seeds indoors (fall) | May 26 – Jun 5 |
| Broccoli | Transplant outdoors (fall) | Jun 25 – Jul 6 |
| Cabbage | Start seeds indoors (spring) | Mar 29 – Apr 26 |
| Cabbage | Transplant outdoors (spring) | Apr 26 – May 27 |
| Cabbage | Start seeds indoors (fall) | May 16 – Jun 15 |
| Cabbage | Transplant outdoors (fall) | Jun 15 – Jul 16 |
| Leaf lettuce | Sow outdoors (spring) | Apr 26 – Jul 12 |
| Leaf lettuce | Sow outdoors (fall) | Jun 15 – Aug 1 |
| Spinach | Sow outdoors (spring) | Apr 19 – Jun 2 |
| Spinach | Sow outdoors (fall) | Jul 2 – Aug 6 |
| Radishes | Sow outdoors (spring) | Apr 26 – Jun 16 |
| Radishes | Sow outdoors (fall) | Jun 15 – Aug 16 |
| Kale | Sow outdoors (spring) | May 13 – Jun 2 |
| Kale | Sow outdoors (fall) | Jun 8 – Jul 16 |
| Carrots | Sow outdoors (spring) | May 27 – Jul 12 |
| Carrots | Sow outdoors (fall) | May 16 – Jul 1 |
| Garlic | Plant outdoors (fall) | Sep 15 – Oct 16 |
Where these dates come from
ZIP code 82450 is matched to the NOAA station Wapiti 1Wsw, WY, 2 km away, at 5,558 ft elevation (29 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wapiti 1Wsw, WY (used) | 5,558 ft | May 27 | Sep 25 |
| Cody 21 Sw, WY | 5,840 ft | May 29 | Sep 18 |
| Buffalo Bill Dam, WY | 5,160 ft | May 17 | Oct 3 |
| Cody, WY | 5,280 ft | May 12 | Oct 1 |
Frost dates near Wapiti
- Cody, WY 82414 · last May 17, first Oct 3
- Meeteetse, WY 82433 · last —, first —
- Ralston, WY 82440 · last May 15, first Sep 25
- Powell, WY 82435 · last May 19, first Sep 20
- Belfry, MT 59008 · last May 18, first Sep 22
- Cooke City, MT 59020 · last —, first —
- Silver Gate, MT 59081 · last —, first —
- Byron, WY 82412 · last May 6, first Oct 1
Frequently asked questions
- When is the last frost in Wapiti, WY?
- For ZIP code 82450, the average last spring frost (32°F) is May 27, based on NOAA 1991-2020 climate normals for the Wapiti 1Wsw, WY weather station. There is a 1-in-10 chance of a frost after June 12.
- When is the first frost in Wapiti, WY?
- The average first fall frost (32°F) is September 25. There is a 1-in-10 chance of frost by September 7, so tender plants are at risk from that point on.
- How long is the growing season in 82450?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 121 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.