Frost dates for 82215Hartville, WY
The average last spring frost in Hartville is May 7 and the average first fall frost is October 6, giving a typical growing season of about 152 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 7
- Average first fall frost
- Oct 6
- Growing season
- 152 days
Safer after May 21 (1-in-10 risk)
Possible by Sep 23 (1-in-10 risk)
Last frost typically in 192 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 5 · May 18 · Jun 1 | Sep 15 · Sep 28 · Oct 10 | 133 days | 100% |
| Frost / freeze (32°F) | Apr 24 · May 7 · May 21 | Sep 23 · Oct 6 · Oct 18 | 152 days | 100% |
| Hard freeze (28°F) | Apr 13 · Apr 28 · May 10 | Oct 1 · Oct 16 · Oct 26 | 171 days | 100% |
Planting calendar for Hartville
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 6 – Jun 12 |
| Tomatoes | Transplant outdoors | May 23 – Jun 16 |
| Peppers | Start seeds indoors | Apr 6 – May 7 |
| Peppers | Transplant outdoors | Jun 6 – Jul 7 |
| Eggplant | Start seeds indoors | Apr 23 – May 22 |
| Eggplant | Transplant outdoors | Jun 6 – Jul 7 |
| Cucumbers | Sow outdoors | Jun 6 – Jun 26 |
| Summer squash | Sow outdoors | May 23 – Jul 7 |
| Winter squash & pumpkins | Sow outdoors | Jun 6 – Jul 7 |
| Snap beans | Sow outdoors | May 23 – Jul 19 |
| Sweet corn | Sow outdoors | May 23 – Jun 16 |
| Watermelon & cantaloupe | Sow outdoors | Jun 6 – Jul 7 |
| Okra | Sow outdoors | May 30 – Jun 22 |
| Peas | Sow outdoors (spring) | Apr 6 – May 22 |
| Potatoes | Plant outdoors (spring) | Apr 6 – Jun 6 |
| Onions | Start seeds indoors (spring) | Feb 23 – Mar 22 |
| Onions | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (spring) | Mar 19 – Apr 22 |
| Broccoli | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (fall) | Jun 6 – Jun 16 |
| Broccoli | Transplant outdoors (fall) | Jul 6 – Jul 17 |
| Cabbage | Start seeds indoors (spring) | Mar 9 – Apr 6 |
| Cabbage | Transplant outdoors (spring) | Apr 6 – May 7 |
| Cabbage | Start seeds indoors (fall) | May 27 – Jun 26 |
| Cabbage | Transplant outdoors (fall) | Jun 26 – Jul 27 |
| Leaf lettuce | Sow outdoors (spring) | Apr 6 – Jun 22 |
| Leaf lettuce | Sow outdoors (fall) | Jun 26 – Aug 12 |
| Spinach | Sow outdoors (spring) | Mar 30 – May 13 |
| Spinach | Sow outdoors (fall) | Jul 13 – Aug 17 |
| Radishes | Sow outdoors (spring) | Apr 6 – May 27 |
| Radishes | Sow outdoors (fall) | Jun 26 – Aug 27 |
| Kale | Sow outdoors (spring) | Apr 23 – May 13 |
| Kale | Sow outdoors (fall) | Jun 19 – Jul 27 |
| Carrots | Sow outdoors (spring) | May 7 – Jun 22 |
| Carrots | Sow outdoors (fall) | May 27 – Jul 12 |
| Garlic | Plant outdoors (fall) | Sep 26 – Oct 27 |
Where these dates come from
ZIP code 82215 is matched to the NOAA station Guernsey 2Nw, WY, 6.4 km away, at 4,480 ft elevation (431 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Guernsey 2Nw, WY (used) | 4,480 ft | May 7 | Oct 6 |
| Guernsey Dam #2, WY | 4,355 ft | May 11 | Oct 3 |
| Whalen Dam Usbr, WY | 4,294 ft | May 7 | Oct 3 |
| Old Ft Laramie, WY | 4,250 ft | May 14 | Sep 26 |
Frost dates near Hartville
- Guernsey, WY 82214 · last May 11, first Oct 3
- Fort Laramie, WY 82212 · last May 14, first Sep 26
- Jay Em, WY 82219 · last May 17, first Sep 28
- Glendo, WY 82213 · last May 9, first Oct 5
- Wheatland, WY 82201 · last May 19, first Sep 22
- Lingle, WY 82223 · last May 11, first Sep 29
- Manville, WY 82227 · last May 23, first Sep 20
- Veteran, WY 82243 · last May 15, first Sep 27
Frequently asked questions
- When is the last frost in Hartville, WY?
- For ZIP code 82215, the average last spring frost (32°F) is May 7, based on NOAA 1991-2020 climate normals for the Guernsey 2Nw, WY weather station. There is a 1-in-10 chance of a frost after May 21.
- When is the first frost in Hartville, WY?
- The average first fall frost (32°F) is October 6. There is a 1-in-10 chance of frost by September 23, so tender plants are at risk from that point on.
- How long is the growing season in 82215?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 152 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.