Frost dates for 80103Byers, CO
The average last spring frost in Byers is May 13 and the average first fall frost is October 2, giving a typical growing season of about 142 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 13
- Average first fall frost
- Oct 2
- Growing season
- 142 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 20 (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 24 · Jun 7 | Sep 11 · Sep 25 · Oct 5 | 122 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 13 · May 30 | Sep 20 · Oct 2 · Oct 14 | 142 days | 100% |
| Hard freeze (28°F) | Apr 19 · May 2 · May 15 | Sep 30 · Oct 10 · Oct 22 | 160 days | 100% |
Planting calendar for Byers
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 12 |
| 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 22 |
| Summer squash | Sow outdoors | May 29 – Jul 13 |
| Winter squash & pumpkins | Sow outdoors | Jun 12 – Jul 13 |
| Snap beans | Sow outdoors | May 29 – Jul 15 |
| Sweet corn | Sow outdoors | May 29 – Jun 12 |
| 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 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 15 – Apr 12 |
| Cabbage | Transplant outdoors (spring) | Apr 12 – May 13 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Apr 12 – Jun 28 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Apr 5 – May 19 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Apr 12 – Jun 2 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | Apr 29 – May 19 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | May 13 – Jun 28 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 80103 is matched to the NOAA station Byers 5 Ene, CO, 7.9 km away, at 5,101 ft elevation (138 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Byers 5 Ene, CO (used) | 5,101 ft | May 13 | Oct 2 |
| Denver Intl Ap, CO | 5,414 ft | May 5 | Oct 9 |
| Elizabeth 2Nw, CO | 6,611 ft | May 16 | Oct 2 |
| Parker, CO | 5,904 ft | May 9 | Oct 3 |
Frost dates near Byers
- Strasburg, CO 80136 · last May 13, first Oct 2
- Deer Trail, CO 80105 · last May 13, first Oct 2
- Aurora, CO 80041 · last May 5, first Oct 9
- Bennett, CO 80102 · last May 5, first Oct 9
- Watkins, CO 80137 · last May 5, first Oct 9
- Agate, CO 80101 · last May 21, first Sep 26
- Roggen, CO 80652 · last May 13, first Oct 2
- Kiowa, CO 80117 · last May 16, first Oct 2
Frequently asked questions
- When is the last frost in Byers, CO?
- For ZIP code 80103, the average last spring frost (32°F) is May 13, based on NOAA 1991-2020 climate normals for the Byers 5 Ene, CO weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Byers, CO?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 80103?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 142 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.