Frost dates for 82310Jeffrey City, WY
The average last spring frost in Jeffrey City is June 1 and the average first fall frost is September 13, giving a typical growing season of about 104 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 1
- Average first fall frost
- Sep 13
- Growing season
- 104 days
Safer after Jun 16 (1-in-10 risk)
Possible by Sep 1 (1-in-10 risk)
Last frost typically in 210 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) | Jun 1 · Jun 15 · Jul 2 | Aug 19 · Sep 3 · Sep 17 | 79 days | 100% |
| Frost / freeze (32°F) | May 17 · Jun 1 · Jun 16 | Sep 1 · Sep 13 · Sep 28 | 104 days | 100% |
| Hard freeze (28°F) | May 4 · May 17 · May 31 | Sep 9 · Sep 24 · Oct 9 | 129 days | 100% |
Planting calendar for Jeffrey City
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 | May 1 – Jul 7 |
| Tomatoes | Transplant outdoors | Jun 17 – May 24 |
| Peppers | Start seeds indoors | May 1 – Jun 1 |
| Peppers | Transplant outdoors | Jul 1 – Aug 1 |
| Eggplant | Start seeds indoors | May 18 – Jun 16 |
| Eggplant | Transplant outdoors | Jul 1 – Aug 1 |
| Cucumbers | Sow outdoors | Jul 1 – Jun 3 |
| Summer squash | Sow outdoors | Jun 17 – Aug 1 |
| Winter squash & pumpkins | Sow outdoors | Jul 1 – Aug 1 |
| Snap beans | Sow outdoors | Jun 17 – Jun 26 |
| Sweet corn | Sow outdoors | Jun 17 – May 24 |
| Watermelon & cantaloupe | Sow outdoors | Jul 1 – Aug 1 |
| Okra | Sow outdoors | Jun 24 – Jul 17 |
| Peas | Sow outdoors (spring) | May 1 – Jun 16 |
| Potatoes | Plant outdoors (spring) | May 1 – Jul 1 |
| Onions | Start seeds indoors (spring) | Mar 20 – Apr 16 |
| Onions | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (spring) | Apr 13 – May 17 |
| Broccoli | Transplant outdoors (spring) | May 18 – Jun 16 |
| Broccoli | Start seeds indoors (fall) | May 14 – May 24 |
| Broccoli | Transplant outdoors (fall) | Jun 13 – Jun 24 |
| Cabbage | Start seeds indoors (spring) | Apr 3 – May 1 |
| Cabbage | Transplant outdoors (spring) | May 1 – Jun 1 |
| Cabbage | Start seeds indoors (fall) | May 4 – Jun 3 |
| Cabbage | Transplant outdoors (fall) | Jun 3 – Jul 4 |
| Leaf lettuce | Sow outdoors (spring) | May 1 – Jul 17 |
| Leaf lettuce | Sow outdoors (fall) | Jun 3 – Jul 20 |
| Spinach | Sow outdoors (spring) | Apr 24 – Jun 7 |
| Spinach | Sow outdoors (fall) | Jun 20 – Jul 25 |
| Radishes | Sow outdoors (spring) | May 1 – Jun 21 |
| Radishes | Sow outdoors (fall) | Jun 3 – Aug 4 |
| Kale | Sow outdoors (spring) | May 18 – Jun 7 |
| Kale | Sow outdoors (fall) | May 27 – Jul 4 |
| Carrots | Sow outdoors (spring) | Jun 1 – Jul 17 |
| Carrots | Sow outdoors (fall) | May 4 – Jun 19 |
| Garlic | Plant outdoors (fall) | Sep 3 – Oct 4 |
Where these dates come from
ZIP code 82310 is matched to the NOAA station Jeffrey City, WY, 6.2 km away, at 6,319 ft elevation (801 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Jeffrey City, WY (used) | 6,319 ft | Jun 1 | Sep 13 |
| Muddy Gap, WY | 6,248 ft | May 21 | Sep 27 |
| Lander 11 Sse, WY | 5,773 ft | May 13 | Oct 2 |
| Riverton, WY | 4,955 ft | May 12 | Sep 24 |
Frost dates near Jeffrey City
- Bairoil, WY 82322 · last May 21, first Sep 27
- Riverton, WY 82501 · last May 12, first Sep 24
- Saint Stephens, WY 82524 · last May 12, first Sep 24
- Arapahoe, WY 82510 · last May 12, first Sep 24
- Hudson, WY 82515 · last May 12, first Sep 24
- Lander, WY 82520 · last May 12, first Sep 24
- Hiland, WY 82638 · last May 30, first Sep 22
- Shoshoni, WY 82649 · last May 7, first Oct 3
Frequently asked questions
- When is the last frost in Jeffrey City, WY?
- For ZIP code 82310, the average last spring frost (32°F) is June 1, based on NOAA 1991-2020 climate normals for the Jeffrey City, WY weather station. There is a 1-in-10 chance of a frost after June 16.
- When is the first frost in Jeffrey City, WY?
- The average first fall frost (32°F) is September 13. There is a 1-in-10 chance of frost by September 1, so tender plants are at risk from that point on.
- How long is the growing season in 82310?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 104 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.