USDA Hardiness Zone 6b
Frost Dates for 81505 — Grand Junction, Colorado
NOAA 1991–2020 normals from Grand Junction Walker Field, CO (4,858 ft), 4 miles northeast.
Updated
In Grand Junction, the last spring frost (32°F) is around April 28 in half of years and has passed by May 14 in nine years out of ten. The first fall frost comes around October 16, as early as October 3 one year in ten, leaving a typical freeze-free season of 171 days (NOAA, Grand Junction Walker Field, CO).
- Last spring frost
- April 28
- First fall frost
- October 16
- Growing season
- 171 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- November 14
- Last snow
- March 30
- Winters with snow
- 100%
- Snow per year
- 17.7"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Grand Junction
Half of springs at Grand Junction Walker Field, CO see their last 32°F night by April 28; only one in ten is past it by April 11, and one in ten still has one after May 14. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 7 20%, and after May 14 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 October 16 in half of years, as early as October 3 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 27; in spring the one-in-ten date for 28°F is May 2, 12 days before the 32°F one. The freeze-free season lasts 171 days in a typical year, longer than at 95% of the 110 Colorado stations; it reaches 190 days one year in ten and falls short of 152 one year in ten. On average 137 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 10 days longer, to about May 8, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 26 and February 18.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 25 | Apr 30 | May 2 | May 5 | May 8 | May 11 | May 15 | May 19 | May 25 |
| 32°F | Apr 11 | Apr 16 | Apr 21 | Apr 25 | Apr 28 | May 1 | May 3 | May 7 | May 14 |
| 28°F | Mar 24 | Apr 2 | Apr 6 | Apr 9 | Apr 13 | Apr 17 | Apr 21 | Apr 26 | May 2 |
| 24°F | Mar 5 | Mar 11 | Mar 16 | Mar 22 | Mar 28 | Apr 1 | Apr 6 | Apr 12 | Apr 21 |
| 20°F | Feb 14 | Feb 21 | Feb 26 | Mar 2 | Mar 5 | Mar 9 | Mar 15 | Mar 22 | Mar 31 |
| 16°F | Jan 31 | Feb 5 | Feb 10 | Feb 14 | Feb 18 | Feb 23 | Feb 27 | Mar 4 | Mar 12 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 24 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 19 |
| 32°F | Oct 3 | Oct 7 | Oct 10 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 29 |
| 28°F | Oct 12 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 2 | Nov 6 | Nov 10 |
| 24°F | Oct 22 | Oct 28 | Nov 1 | Nov 5 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 20 |
| 20°F | Nov 1 | Nov 6 | Nov 10 | Nov 14 | Nov 17 | Nov 19 | Nov 22 | Nov 25 | Nov 30 |
| 16°F | Nov 10 | Nov 16 | Nov 20 | Nov 24 | Nov 26 | Nov 29 | Dec 2 | Dec 7 | Dec 13 |
Freeze probabilities 1991–2020 at Grand Junction Walker Field, 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 81505 →Compare Grand Junction with another place →
Weather by month in Grand Junction
July is the warmest month at Grand Junction Walker Field, CO, averaging 95°F by day and 64°F at night; January is the coldest at 38°F and 17°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 40% of years.
Warmth for growing adds up to 3,634 growing degree days a year (base 50°F), more than at 95% of the 110 Colorado stations. 34% of them (1,231) have built up by the end of June, and July adds the most, 905. Precipitation totals 9.0 inches a year, most in September (1.2") and least in June (0.4"); May to September bring 43% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 38 | 17 | 0.6 | 100% | 30 | 0 |
| Feb | 46 | 24 | 0.5 | 100% | 24 | 1 |
| Mar | 58 | 32 | 0.8 | 100% | 17 | 32 |
| Apr | 66 | 38 | 1.0 | 97% | 6 | 129 |
| May | 77 | 47 | 0.8 | 40% | 1 | 379 |
| Jun | 89 | 57 | 0.4 | 0% | 0 | 690 |
| Jul | 95 | 64 | 0.6 | 0% | 0 | 905 |
| Aug | 91 | 62 | 0.9 | 0% | 0 | 814 |
| Sep | 82 | 53 | 1.2 | 5% | <1 | 515 |
| Oct | 67 | 40 | 1.0 | 93% | 6 | 159 |
| Nov | 52 | 28 | 0.6 | 100% | 23 | 10 |
| Dec | 39 | 18 | 0.6 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Grand Junction Walker Field, CO (4,858 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, Grand Junction WFO, CO, 4 miles east of Grand Junction, has a last frost 14 days earlier (April 14), a first frost 7 days later (October 23), a season 19 days longer.
When it snows in Grand Junction, Colorado
The first measurable snow (0.1 inch or more) in Grand Junction usually arrives around November 14, and the last of the season around March 30. Those are the middle dates across the winters of 1991–2020 at Grand Junction Walker Field, CO, 3.8 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 29 days after the last snow.
Planting calendar for 81505
| When | What to do |
|---|---|
| February 17 – March 3 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 3 – March 17 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 31 – April 14 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 28 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 24 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 2 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 16 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 81505 is 4 miles from Grand Junction Walker Field, CO, which stands at 4,858 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81505 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°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.