USDA Hardiness Zone 5b
Frost Dates for 81230 — Gunnison, Colorado
NOAA 1991–2020 normals from Cochetopa Creek, CO (8,006 ft), 11 miles east.
Updated
In Gunnison, the last spring frost (32°F) is around June 21 in half of years and has passed by July 7 in nine years out of ten. The first fall frost comes around September 5, as early as August 21 one year in ten, leaving a typical freeze-free season of 74 days (NOAA, Cochetopa Creek, CO).
- Last spring frost
- June 21
- First fall frost
- September 5
- Growing season
- 74 days
- Hardiness zone
- 5b
50% probability
50% probability
freeze-free, 50%
-15 to -10°F (-26.1 to -23.3°C) coldest night
- First snow
- October 29
- Last snow
- April 27
- Winters with snow
- 100%
- Snow per year
- 45.5"
median, 1991–2020
median, 1991–2020
28 of 28 observed
NOAA normal
Frost risk by date in Gunnison
Half of springs at Cochetopa Creek, CO see their last 32°F night by June 21; only one in ten is past it by June 7, and one in ten still has one after July 7. Planting tender crops after June 27 leaves a 30% risk of a frost on them, after June 30 20%, and after July 7 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 75% of the 110 Colorado stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 5 in half of years, as early as August 21 one year in ten, and holds off past September 16 one year in ten. A hard freeze of 28°F follows 11 days later, around September 16; in spring the one-in-ten date for 28°F is June 22, 15 days before the 32°F one. The freeze-free season lasts 74 days in a typical year, shorter than at 99% of the 110 Colorado stations; it reaches 92 days one year in ten and falls short of 52 one year in ten. On average 246 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 14 and April 22.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Jun 7 | Jun 12 | Jun 16 | Jun 18 | Jun 21 | Jun 24 | Jun 27 | Jun 30 | Jul 7 |
| 28°F | May 24 | May 29 | Jun 1 | Jun 4 | Jun 7 | Jun 10 | Jun 13 | Jun 16 | Jun 22 |
| 24°F | May 7 | May 14 | May 18 | May 20 | May 23 | May 27 | May 30 | Jun 3 | Jun 9 |
| 20°F | Apr 22 | Apr 27 | May 1 | May 3 | May 7 | May 10 | May 14 | May 17 | May 22 |
| 16°F | Apr 6 | Apr 11 | Apr 14 | Apr 18 | Apr 22 | Apr 26 | Apr 29 | May 3 | May 8 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Aug 21 | Aug 27 | Sep 1 | Sep 3 | Sep 5 | Sep 7 | Sep 10 | Sep 12 | Sep 16 |
| 28°F | Sep 4 | Sep 9 | Sep 11 | Sep 13 | Sep 16 | Sep 18 | Sep 21 | Sep 23 | Sep 26 |
| 24°F | Sep 13 | Sep 19 | Sep 22 | Sep 24 | Sep 26 | Sep 28 | Sep 30 | Oct 2 | Oct 6 |
| 20°F | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 17 |
| 16°F | Sep 30 | Oct 4 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 28 |
Freeze probabilities 1991–2020 at Cochetopa Creek, CO, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 81230 →Compare Gunnison with another place →
Weather by month in Gunnison
July is the warmest month at Cochetopa Creek, CO, averaging 80°F by day and 44°F at night; January is the coldest at 28°F and -4°F. A freezing night is all but certain in every month from September to June (a 90% chance or more). No month is safe from a 32°F night: even the warmest has at least a 10% chance. In spring, July still brings one in 20% of years.
Warmth for growing adds up to 1,014 growing degree days a year (base 50°F), fewer than at 90% of the 110 Colorado stations. 23% of them (228) have built up by the end of June, and July adds the most, 358. Precipitation totals 10.7 inches a year, most in August (1.5") and least in June (0.6"); May to September bring 52% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 28 | -4 | 0.7 | 100% | 31 | 0 |
| Feb | 32 | 2 | 0.7 | 100% | 28 | 0 |
| Mar | 44 | 14 | 0.7 | 100% | 31 | 0 |
| Apr | 55 | 22 | 0.9 | 100% | 28 | 3 |
| May | 65 | 29 | 1.0 | 100% | 21 | 37 |
| Jun | 75 | 36 | 0.6 | 97% | 6 | 189 |
| Jul | 80 | 44 | 1.4 | 20% | <1 | 358 |
| Aug | 78 | 42 | 1.5 | 29% | 1 | 307 |
| Sep | 72 | 33 | 1.1 | 100% | 13 | 115 |
| Oct | 60 | 22 | 0.7 | 100% | 28 | 6 |
| Nov | 44 | 11 | 0.6 | 100% | 30 | 0 |
| Dec | 30 | -1 | 0.8 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Cochetopa Creek, CO (8,006 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Taylor Park, CO, 31 miles northeast of Gunnison and 1,173 feet higher, has a last frost 1 day earlier (June 20), a first frost 3 days later (September 8), a season 6 days longer.
When it snows in Gunnison, Colorado
The first measurable snow (0.1 inch or more) in Gunnison usually arrives around October 29, and the last of the season around April 27. Those are the middle dates across the winters of 1991–2020 at Gunnison 3SW, CO, 4.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 55 days after the last snow.
Planting calendar for 81230
| When | What to do |
|---|---|
| April 12 – April 26 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 26 – May 10 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 24 – June 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 5 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 81230 is 11 miles from Cochetopa Creek, CO, which stands at 8,006 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81230 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.