Frost dates for 82831Arvada, WY
The average last spring frost in Arvada is May 21 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 21
- Average first fall frost
- Sep 23
- Growing season
- 123 days
Safer after Jun 3 (1-in-10 risk)
Possible by Sep 8 (1-in-10 risk)
Last frost typically in 206 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 20 · Jun 2 · Jun 20 | Aug 30 · Sep 12 · Sep 24 | 99 days | 100% |
| Frost / freeze (32°F) | May 9 · May 21 · Jun 3 | Sep 8 · Sep 23 · Oct 5 | 123 days | 100% |
| Hard freeze (28°F) | Apr 28 · May 10 · May 24 | Sep 18 · Oct 2 · Oct 16 | 145 days | 100% |
Planting calendar for Arvada
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 20 – Jun 26 |
| Tomatoes | Transplant outdoors | Jun 6 – Jun 3 |
| Peppers | Start seeds indoors | Apr 20 – May 21 |
| Peppers | Transplant outdoors | Jun 20 – Jul 21 |
| Eggplant | Start seeds indoors | May 7 – Jun 5 |
| Eggplant | Transplant outdoors | Jun 20 – Jul 21 |
| Cucumbers | Sow outdoors | Jun 20 – Jun 13 |
| Summer squash | Sow outdoors | Jun 6 – Jul 21 |
| Winter squash & pumpkins | Sow outdoors | Jun 20 – Jul 21 |
| Snap beans | Sow outdoors | Jun 6 – Jul 6 |
| Sweet corn | Sow outdoors | Jun 6 – Jun 3 |
| Watermelon & cantaloupe | Sow outdoors | Jun 20 – Jul 21 |
| Okra | Sow outdoors | Jun 13 – Jul 6 |
| Peas | Sow outdoors (spring) | Apr 20 – Jun 5 |
| Potatoes | Plant outdoors (spring) | Apr 20 – Jun 20 |
| Onions | Start seeds indoors (spring) | Mar 9 – Apr 5 |
| Onions | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (spring) | Apr 2 – May 6 |
| Broccoli | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (fall) | May 24 – Jun 3 |
| Broccoli | Transplant outdoors (fall) | Jun 23 – Jul 4 |
| Cabbage | Start seeds indoors (spring) | Mar 23 – Apr 20 |
| Cabbage | Transplant outdoors (spring) | Apr 20 – May 21 |
| Cabbage | Start seeds indoors (fall) | May 14 – Jun 13 |
| Cabbage | Transplant outdoors (fall) | Jun 13 – Jul 14 |
| Leaf lettuce | Sow outdoors (spring) | Apr 20 – Jul 6 |
| Leaf lettuce | Sow outdoors (fall) | Jun 13 – Jul 30 |
| Spinach | Sow outdoors (spring) | Apr 13 – May 27 |
| Spinach | Sow outdoors (fall) | Jun 30 – Aug 4 |
| Radishes | Sow outdoors (spring) | Apr 20 – Jun 10 |
| Radishes | Sow outdoors (fall) | Jun 13 – Aug 14 |
| Kale | Sow outdoors (spring) | May 7 – May 27 |
| Kale | Sow outdoors (fall) | Jun 6 – Jul 14 |
| Carrots | Sow outdoors (spring) | May 21 – Jul 6 |
| Carrots | Sow outdoors (fall) | May 14 – Jun 29 |
| Garlic | Plant outdoors (fall) | Sep 13 – Oct 14 |
Where these dates come from
ZIP code 82831 is matched to the NOAA station Echeta 2 Nw, WY, 28.4 km away, at 4,000 ft elevation (391 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Echeta 2 Nw, WY (used) | 4,000 ft | May 21 | Sep 23 |
| Leiter 9N, WY | 4,160 ft | May 14 | Sep 30 |
| Clearmont 5 Sw, WY | 3,995 ft | May 24 | Sep 16 |
| Buffalo Johnson Co Ap, WY | 4,967 ft | May 13 | Oct 1 |
Frost dates near Arvada
- Leiter, WY 82837 · last May 24, first Sep 16
- Clearmont, WY 82835 · last May 24, first Sep 16
- Recluse, WY 82725 · last May 21, first Sep 23
- Otter, MT 59062 · last May 25, first Sep 19
- Wyarno, WY 82845 · last May 21, first Sep 23
- Banner, WY 82832 · last May 24, first Sep 21
- Weston, WY 82731 · last May 23, first Sep 18
- Buffalo, WY 82834 · last May 24, first Sep 21
Frequently asked questions
- When is the last frost in Arvada, WY?
- For ZIP code 82831, the average last spring frost (32°F) is May 21, based on NOAA 1991-2020 climate normals for the Echeta 2 Nw, WY weather station. There is a 1-in-10 chance of a frost after June 3.
- When is the first frost in Arvada, WY?
- The average first fall frost (32°F) is September 23. There is a 1-in-10 chance of frost by September 8, so tender plants are at risk from that point on.
- How long is the growing season in 82831?
- 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.