USDA Hardiness Zone 5b
Frost Dates for 81637 — Gypsum, Colorado
NOAA 1991–2020 normals from Shoshone, CO (5,992 ft), 14 miles southwest.
Updated
In Gypsum, the last spring frost (32°F) is around May 1 in half of years and has passed by May 14 in nine years out of ten. The first fall frost comes around October 14, as early as October 1 one year in ten, leaving a typical freeze-free season of 164 days (NOAA, Shoshone, CO).
- Last spring frost
- May 1
- First fall frost
- October 14
- Growing season
- 164 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
- November 24
- Last snow
- February 24
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
18 of 18 observed
NOAA normal
Frost risk by date in Gypsum
Half of springs at Shoshone, CO see their last 32°F night by May 1; only one in ten is past it by April 19, and one in ten still has one after May 14. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 9 20%, and after May 14 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 110 Colorado stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 14 in half of years, as early as October 1 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 9 days later, around October 23; in spring the one-in-ten date for 28°F is May 4, 10 days before the 32°F one. The freeze-free season lasts 164 days in a typical year, longer than at 88% of the 110 Colorado stations; it reaches 181 days one year in ten and falls short of 146 one year in ten. On average 143 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 13 days longer, to about May 14, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 19 and March 13.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 1 | May 4 | May 7 | May 10 | May 14 | May 17 | May 21 | May 25 | Jun 1 |
| 32°F | Apr 19 | Apr 24 | Apr 28 | Apr 30 | May 1 | May 4 | May 6 | May 9 | May 14 |
| 28°F | Apr 6 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 4 |
| 24°F | Mar 20 | Mar 29 | Apr 1 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 19 | Apr 24 |
| 20°F | Mar 8 | Mar 13 | Mar 17 | Mar 22 | Mar 26 | Mar 30 | Apr 2 | Apr 6 | Apr 12 |
| 16°F | Feb 24 | Mar 2 | Mar 6 | Mar 9 | Mar 13 | Mar 17 | Mar 21 | Mar 27 | Apr 2 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 25 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 8 | Oct 11 | Oct 13 | Oct 17 |
| 32°F | Oct 1 | Oct 6 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 27 |
| 28°F | Oct 11 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 25 | Oct 29 | Nov 1 | Nov 6 |
| 24°F | Oct 19 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 16 |
| 20°F | Oct 26 | Oct 30 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 17 | Nov 20 | Nov 24 |
| 16°F | Nov 3 | Nov 8 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 24 | Nov 28 | Dec 3 |
Freeze probabilities 1991–2020 at Shoshone, 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 81637 →Compare Gypsum with another place →
Compared with the next station
The nearest other station, Glenwood Spgs #2, CO, 20 miles southwest of Gypsum, has a last frost 12 days later (May 13), a first frost 11 days earlier (October 3), a season 22 days shorter.
When it snows in Gypsum, Colorado
The first measurable snow (0.1 inch or more) in Gypsum usually arrives around November 24, and the last of the season around February 24. Those are the middle dates across the winters of 1991–2020 at Shoshone, CO, 13.5 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 66 days after the last snow.
Planting calendar for 81637
| When | What to do |
|---|---|
| February 20 – March 6 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 6 – March 20 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 3 – April 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 1 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 22 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 30 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 14 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 81637 is 14 miles from Shoshone, CO, which stands at 5,992 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81637 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.