Frost dates for 82701Newcastle, WY
The average last spring frost in Newcastle is May 13 and the average first fall frost is October 3, giving a typical growing season of about 143 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 13
- Average first fall frost
- Oct 3
- Growing season
- 143 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 17 (1-in-10 risk)
Last frost typically in 198 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 11 · May 23 · Jun 7 | Sep 9 · Sep 24 · Oct 7 | 122 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 13 · May 26 | Sep 17 · Oct 3 · Oct 16 | 143 days | 100% |
| Hard freeze (28°F) | Apr 16 · May 1 · May 17 | Sep 27 · Oct 11 · Oct 25 | 162 days | 100% |
Planting calendar for Newcastle
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 12 – Jun 18 |
| Tomatoes | Transplant outdoors | May 29 – Jun 13 |
| Peppers | Start seeds indoors | Apr 12 – May 13 |
| Peppers | Transplant outdoors | Jun 12 – Jul 13 |
| Eggplant | Start seeds indoors | Apr 29 – May 28 |
| Eggplant | Transplant outdoors | Jun 12 – Jul 13 |
| Cucumbers | Sow outdoors | Jun 12 – Jun 23 |
| Summer squash | Sow outdoors | May 29 – Jul 13 |
| Winter squash & pumpkins | Sow outdoors | Jun 12 – Jul 13 |
| Snap beans | Sow outdoors | May 29 – Jul 16 |
| Sweet corn | Sow outdoors | May 29 – Jun 13 |
| Watermelon & cantaloupe | Sow outdoors | Jun 12 – Jul 13 |
| Okra | Sow outdoors | Jun 5 – Jun 28 |
| Peas | Sow outdoors (spring) | Apr 12 – May 28 |
| Potatoes | Plant outdoors (spring) | Apr 12 – Jun 12 |
| Onions | Start seeds indoors (spring) | Mar 1 – Mar 28 |
| Onions | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (spring) | Mar 25 – Apr 28 |
| Broccoli | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (fall) | Jun 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 15 – Apr 12 |
| Cabbage | Transplant outdoors (spring) | Apr 12 – May 13 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 12 – Jun 28 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Apr 5 – May 19 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 12 – Jun 2 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 29 – May 19 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 13 – Jun 28 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 82701 is matched to the NOAA station Newcastle, WY, 3 km away, at 4,415 ft elevation (183 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Newcastle, WY (used) | 4,415 ft | May 13 | Oct 3 |
| Edgemont 23 Nnw, SD | 4,402 ft | May 18 | Sep 27 |
| Upton, WY | 4,320 ft | May 20 | Sep 23 |
| Rochford 2 Wnw, SD | 5,450 ft | — | — |
Frost dates near Newcastle
- Osage, WY 82723 · last May 20, first Sep 23
- Four Corners, WY 82715 · last —, first —
- Upton, WY 82730 · last May 20, first Sep 23
- Hill City, SD 57745 · last Jun 1, first Sep 10
- Lead, SD 57754 · last May 18, first Sep 29
- Pringle, SD 57773 · last Jun 1, first Sep 10
- Sundance, WY 82729 · last May 21, first Sep 25
- Keystone, SD 57751 · last May 28, first Sep 18
Frequently asked questions
- When is the last frost in Newcastle, WY?
- For ZIP code 82701, the average last spring frost (32°F) is May 13, based on NOAA 1991-2020 climate normals for the Newcastle, WY weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Newcastle, WY?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 17, so tender plants are at risk from that point on.
- How long is the growing season in 82701?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 143 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.