Frost dates for 82412Byron, WY
The average last spring frost in Byron is May 6 and the average first fall frost is October 1, giving a typical growing season of about 148 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 6
- Average first fall frost
- Oct 1
- Growing season
- 148 days
Safer after May 20 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 188 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 6 · May 19 · Jun 4 | Sep 9 · Sep 23 · Oct 5 | 123 days | 100% |
| Frost / freeze (32°F) | Apr 26 · May 6 · May 20 | Sep 19 · Oct 1 · Oct 16 | 148 days | 100% |
| Hard freeze (28°F) | Apr 13 · Apr 27 · May 9 | Sep 27 · Oct 12 · Oct 25 | 168 days | 100% |
Planting calendar for Byron
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 5 – Jun 11 |
| Tomatoes | Transplant outdoors | May 22 – Jun 11 |
| Peppers | Start seeds indoors | Apr 5 – May 6 |
| Peppers | Transplant outdoors | Jun 5 – Jul 6 |
| Eggplant | Start seeds indoors | Apr 22 – May 21 |
| Eggplant | Transplant outdoors | Jun 5 – Jul 6 |
| Cucumbers | Sow outdoors | Jun 5 – Jun 21 |
| Summer squash | Sow outdoors | May 22 – Jul 6 |
| Winter squash & pumpkins | Sow outdoors | Jun 5 – Jul 6 |
| Snap beans | Sow outdoors | May 22 – Jul 14 |
| Sweet corn | Sow outdoors | May 22 – Jun 11 |
| Watermelon & cantaloupe | Sow outdoors | Jun 5 – Jul 6 |
| Okra | Sow outdoors | May 29 – Jun 21 |
| Peas | Sow outdoors (spring) | Apr 5 – May 21 |
| Potatoes | Plant outdoors (spring) | Apr 5 – Jun 5 |
| Onions | Start seeds indoors (spring) | Feb 22 – Mar 21 |
| Onions | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (spring) | Mar 18 – Apr 21 |
| Broccoli | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (fall) | Jun 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 8 – Apr 5 |
| Cabbage | Transplant outdoors (spring) | Apr 5 – May 6 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 5 – Jun 21 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Mar 29 – May 12 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 5 – May 26 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | Apr 22 – May 12 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 6 – Jun 21 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 82412 is matched to the NOAA station Deaver, WY, 12.6 km away, at 4,105 ft elevation (96 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Deaver, WY (used) | 4,105 ft | May 6 | Oct 1 |
| Lovell, WY | 3,847 ft | May 9 | Sep 29 |
| Powell Fld Stn, WY | 4,372 ft | May 19 | Sep 20 |
| Heart Mtn, WY | 4,790 ft | May 15 | Sep 25 |
Frost dates near Byron
- Lovell, WY 82431 · last May 9, first Sep 29
- Cowley, WY 82420 · last May 9, first Sep 29
- Deaver, WY 82421 · last May 6, first Oct 1
- Powell, WY 82435 · last May 19, first Sep 20
- Frannie, WY 82423 · last May 6, first Oct 1
- Ralston, WY 82440 · last May 15, first Sep 25
- Emblem, WY 82422 · last May 12, first Sep 28
- Burlington, WY 82411 · last May 12, first Sep 28
Frequently asked questions
- When is the last frost in Byron, WY?
- For ZIP code 82412, the average last spring frost (32°F) is May 6, based on NOAA 1991-2020 climate normals for the Deaver, WY weather station. There is a 1-in-10 chance of a frost after May 20.
- When is the first frost in Byron, WY?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 82412?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 148 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.