Frost Dates for Aurora, CO
In Aurora, CO, the average last spring frost is around May 7 and the average first fall frost around Oct 8, for a growing season of about 152 days. For frost-tender plants, wait until May 21, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Cherry Creek Dam, CO weather station, 8 miles away, elevation 5,647 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | May 21 | Sep 25 |
| 20% | May 15 | Sep 29 |
| 30% | May 12 | Oct 2 |
| 40% | May 10 | Oct 5 |
| 50% | May 7 | Oct 8 |
| 60% | May 5 | Oct 10 |
| 70% | May 3 | Oct 13 |
| 80% | Apr 30 | Oct 16 |
| 90% | Apr 26 | Oct 19 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | May 18 | Sep 30 |
| Frost / freeze (32°F) | May 7 | Oct 8 |
| Hard freeze (28°F) | Apr 29 | Oct 15 |
Planting calendar for Aurora
Transplant May 14 – May 28
Transplant May 21 – Jun 4
Transplant May 21 – Jun 4
Transplant May 14 – May 28
Sow or transplant May 14 – May 28
Sow or transplant May 14 – May 28
Sow or transplant May 21 – Jun 4
Sow or transplant Apr 9 – Apr 23
Fall sowing Aug 13 – Sep 10
Fall sowing Aug 13 – Sep 3
Fall sowing Jul 30 – Aug 13
Sow or transplant Apr 9 – Apr 23
Fall sowing Jul 30 – Aug 27
Transplant Apr 23 – May 7
Fall sowing Jul 16 – Jul 30
Transplant Apr 16 – Apr 30
Fall sowing Jul 16 – Jul 30
Fall sowing Jul 16 – Jul 30
Fall sowing Aug 27 – Sep 17
Fall sowing Jul 30 – Aug 13
Plant Apr 9 – Apr 23
Based on the average last frost (May 7) and first frost (Oct 8). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.