Frost dates for 82723Osage, WY
The average last spring frost in Osage is May 20 and the average first fall frost is September 23, giving a typical growing season of about 123 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 20
- Average first fall frost
- Sep 23
- Growing season
- 123 days
Safer after Jun 4 (1-in-10 risk)
Possible by Sep 7 (1-in-10 risk)
Last frost typically in 205 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 19 · Jun 1 · Jun 20 | Aug 30 · Sep 13 · Sep 26 | 101 days | 100% |
| Frost / freeze (32°F) | May 8 · May 20 · Jun 4 | Sep 7 · Sep 23 · Oct 5 | 123 days | 100% |
| Hard freeze (28°F) | Apr 26 · May 9 · May 24 | Sep 16 · Oct 2 · Oct 15 | 145 days | 100% |
Planting calendar for Osage
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 19 – Jun 25 |
| Tomatoes | Transplant outdoors | Jun 5 – Jun 3 |
| Peppers | Start seeds indoors | Apr 19 – May 20 |
| Peppers | Transplant outdoors | Jun 19 – Jul 20 |
| Eggplant | Start seeds indoors | May 6 – Jun 4 |
| Eggplant | Transplant outdoors | Jun 19 – Jul 20 |
| Cucumbers | Sow outdoors | Jun 19 – Jun 13 |
| Summer squash | Sow outdoors | Jun 5 – Jul 20 |
| Winter squash & pumpkins | Sow outdoors | Jun 19 – Jul 20 |
| Snap beans | Sow outdoors | Jun 5 – Jul 6 |
| Sweet corn | Sow outdoors | Jun 5 – Jun 3 |
| Watermelon & cantaloupe | Sow outdoors | Jun 19 – Jul 20 |
| Okra | Sow outdoors | Jun 12 – Jul 5 |
| Peas | Sow outdoors (spring) | Apr 19 – Jun 4 |
| Potatoes | Plant outdoors (spring) | Apr 19 – Jun 19 |
| Onions | Start seeds indoors (spring) | Mar 8 – Apr 4 |
| Onions | Transplant outdoors (spring) | May 6 – Jun 4 |
| Broccoli | Start seeds indoors (spring) | Apr 1 – May 5 |
| Broccoli | Transplant outdoors (spring) | May 6 – Jun 4 |
| Broccoli | Start seeds indoors (fall) | May 24 – Jun 3 |
| Broccoli | Transplant outdoors (fall) | Jun 23 – Jul 4 |
| Cabbage | Start seeds indoors (spring) | Mar 22 – Apr 19 |
| Cabbage | Transplant outdoors (spring) | Apr 19 – May 20 |
| Cabbage | Start seeds indoors (fall) | May 14 – Jun 13 |
| Cabbage | Transplant outdoors (fall) | Jun 13 – Jul 14 |
| Leaf lettuce | Sow outdoors (spring) | Apr 19 – Jul 5 |
| Leaf lettuce | Sow outdoors (fall) | Jun 13 – Jul 30 |
| Spinach | Sow outdoors (spring) | Apr 12 – May 26 |
| Spinach | Sow outdoors (fall) | Jun 30 – Aug 4 |
| Radishes | Sow outdoors (spring) | Apr 19 – Jun 9 |
| Radishes | Sow outdoors (fall) | Jun 13 – Aug 14 |
| Kale | Sow outdoors (spring) | May 6 – May 26 |
| Kale | Sow outdoors (fall) | Jun 6 – Jul 14 |
| Carrots | Sow outdoors (spring) | May 20 – Jul 5 |
| Carrots | Sow outdoors (fall) | May 14 – Jun 29 |
| Garlic | Plant outdoors (fall) | Sep 13 – Oct 14 |
Where these dates come from
ZIP code 82723 is matched to the NOAA station Upton, WY, 18.3 km away, at 4,320 ft elevation (24 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Upton, WY (used) | 4,320 ft | May 20 | Sep 23 |
| Newcastle, WY | 4,415 ft | May 13 | Oct 3 |
| Sundance, WY | 4,695 ft | May 21 | Sep 25 |
| Moorcroft 3S, WY | 4,325 ft | May 22 | Sep 28 |
Frost dates near Osage
- Upton, WY 82730 · last May 20, first Sep 23
- Newcastle, WY 82701 · last May 13, first Oct 3
- Four Corners, WY 82715 · last —, first —
- Sundance, WY 82729 · last May 21, first Sep 25
- Lead, SD 57754 · last May 18, first Sep 29
- Moorcroft, WY 82721 · last May 21, first Sep 25
- Devils Tower, WY 82714 · last May 23, first Sep 20
- Beulah, WY 82712 · last May 12, first Oct 2
Frequently asked questions
- When is the last frost in Osage, WY?
- For ZIP code 82723, the average last spring frost (32°F) is May 20, based on NOAA 1991-2020 climate normals for the Upton, WY weather station. There is a 1-in-10 chance of a frost after June 4.
- When is the first frost in Osage, WY?
- The average first fall frost (32°F) is September 23. 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 82723?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 123 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.