USDA Hardiness Zone 5b
Frost Dates for 80487 — Steamboat Springs, Colorado
NOAA 1991–2020 normals from Steamboat Springs, CO (6,866 ft), 3 miles east.
Updated
In Steamboat Springs, the last spring frost (32°F) is around June 9 in half of years and has passed by June 24 in nine years out of ten. The first fall frost comes around September 12, as early as August 31 one year in ten, leaving a typical freeze-free season of 93 days (NOAA, Steamboat Springs, CO).
- Last spring frost
- June 9
- First fall frost
- September 12
- Growing season
- 93 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 9
- Last snow
- May 8
- Winters with snow
- 100%
- Snow per year
- 184.5"
median, 1991–2020
median, 1991–2020
23 of 23 observed
NOAA normal
Frost risk by date in Steamboat Springs
Half of springs at Steamboat Springs, CO see their last 32°F night by June 9; only one in ten is past it by May 25, and one in ten still has one after June 24. Planting tender crops after June 14 leaves a 30% risk of a frost on them, after June 18 20%, and after June 24 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 56% of the 110 Colorado stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 12 in half of years, as early as August 31 one year in ten, and holds off past September 24 one year in ten. A hard freeze of 28°F follows 11 days later, around September 23; in spring the one-in-ten date for 28°F is June 6, 18 days before the 32°F one. The freeze-free season lasts 93 days in a typical year, shorter than at 87% of the 110 Colorado stations; it reaches 111 days one year in ten and falls short of 75 one year in ten. On average 233 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 27 and April 6.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | May 25 | May 31 | Jun 4 | Jun 6 | Jun 9 | Jun 11 | Jun 14 | Jun 18 | Jun 24 |
| 28°F | May 2 | May 7 | May 12 | May 16 | May 20 | May 23 | May 28 | Jun 1 | Jun 6 |
| 24°F | Apr 14 | Apr 20 | Apr 25 | Apr 29 | May 2 | May 5 | May 9 | May 14 | May 21 |
| 20°F | Apr 4 | Apr 7 | Apr 11 | Apr 14 | Apr 18 | Apr 22 | Apr 26 | May 1 | May 7 |
| 16°F | Mar 21 | Mar 28 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 13 | Apr 19 | Apr 24 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Aug 31 | Sep 4 | Sep 7 | Sep 9 | Sep 12 | Sep 14 | Sep 17 | Sep 20 | Sep 24 |
| 28°F | Sep 9 | Sep 14 | Sep 17 | Sep 20 | Sep 23 | Sep 26 | Sep 28 | Oct 2 | Oct 6 |
| 24°F | Sep 20 | Sep 24 | Sep 27 | Oct 1 | Oct 4 | Oct 6 | Oct 10 | Oct 13 | Oct 19 |
| 20°F | Sep 30 | Oct 4 | Oct 9 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Oct 30 |
| 16°F | Oct 9 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Oct 31 | Nov 1 | Nov 5 | Nov 10 |
Freeze probabilities 1991–2020 at Steamboat Springs, 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 80487 →Compare Steamboat Springs with another place →
Weather by month in Steamboat Springs
July is the warmest month at Steamboat Springs, CO, averaging 83°F by day and 46°F at night; January is the coldest at 29°F and 5°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). July is the only month with under a 10% chance of a 32°F night. In spring, June still brings one in 79% of years.
Warmth for growing adds up to 1,359 growing degree days a year (base 50°F), fewer than at 83% of the 110 Colorado stations. 24% of them (324) have built up by the end of June, and July adds the most, 448. Precipitation totals 24.7 inches a year, most in May (2.7") and least in March (1.6"); May to September bring 41% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 29 | 5 | 2.5 | 100% | 31 | 0 |
| Feb | 34 | 8 | 1.9 | 100% | 28 | 0 |
| Mar | 45 | 18 | 1.6 | 100% | 30 | 0 |
| Apr | 54 | 27 | 2.5 | 100% | 27 | 8 |
| May | 65 | 34 | 2.7 | 99% | 14 | 79 |
| Jun | 76 | 39 | 1.6 | 79% | 3 | 237 |
| Jul | 83 | 46 | 1.7 | 4% | <1 | 448 |
| Aug | 82 | 44 | 1.8 | 11% | <1 | 399 |
| Sep | 74 | 36 | 2.3 | 96% | 11 | 170 |
| Oct | 59 | 26 | 2.2 | 100% | 27 | 18 |
| Nov | 43 | 16 | 1.9 | 100% | 30 | 0 |
| Dec | 30 | 6 | 2.0 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Steamboat Springs, CO (6,866 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, Hayden, CO, 20 miles west of Steamboat Springs and 399 feet lower, has a last frost 8 days earlier (June 1), a first frost 8 days later (September 20), a season 16 days longer.
When it snows in Steamboat Springs, Colorado
The first measurable snow (0.1 inch or more) in Steamboat Springs usually arrives around October 9, and the last of the season around May 8. Those are the middle dates across the winters of 1991–2020 at Steamboat Springs, CO, 2.9 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 32 days after the last snow.
Planting calendar for 80487
| When | What to do |
|---|---|
| March 31 – April 14 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 14 – April 28 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 12 – May 26 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 9 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 20 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 29 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 12 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 80487 is 3 miles from Steamboat Springs, CO, which stands at 6,866 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 80487 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.