USDA Hardiness Zone 5a
Frost Dates for 82331 — Saratoga, Wyoming
NOAA 1991–2020 normals from Saratoga 4N, WY (6,801 ft), 3 miles northwest.
Updated
In Saratoga, the last spring frost (32°F) is around June 12 in half of years and has passed by June 30 in nine years out of ten. The first fall frost comes around September 7, as early as August 22 one year in ten, leaving a typical freeze-free season of 83 days (NOAA, Saratoga 4N, WY).
- Last spring frost
- June 12
- First fall frost
- September 7
- Growing season
- 83 days
- Hardiness zone
- 5a
50% probability
50% probability
freeze-free, 50%
-20 to -15°F (-28.9 to -26.1°C) coldest night
- First snow
- October 9
- Last snow
- April 26
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
17 of 17 observed
NOAA normal
Frost risk by date in Saratoga
Half of springs at Saratoga 4N, WY see their last 32°F night by June 12; only one in ten is past it by May 25, and one in ten still has one after June 30. Planting tender crops after June 19 leaves a 30% risk of a frost on them, after June 24 20%, and after June 30 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 85% of the 33 Wyoming stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 7 in half of years, as early as August 22 one year in ten, and holds off past September 19 one year in ten. A hard freeze of 28°F follows 9 days later, around September 16; in spring the one-in-ten date for 28°F is June 16, 14 days before the 32°F one. The freeze-free season lasts 83 days in a typical year, shorter than at 94% of the 33 Wyoming stations; it reaches 107 days one year in ten and falls short of 58 one year in ten. On average 229 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 18 and April 15.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | May 25 | May 31 | Jun 3 | Jun 7 | Jun 12 | Jun 15 | Jun 19 | Jun 24 | Jun 30 |
| 28°F | May 9 | May 14 | May 18 | May 22 | May 25 | May 30 | Jun 2 | Jun 6 | Jun 16 |
| 24°F | Apr 27 | May 1 | May 3 | May 6 | May 9 | May 12 | May 15 | May 20 | May 28 |
| 20°F | Apr 11 | Apr 16 | Apr 21 | Apr 25 | Apr 29 | May 1 | May 4 | May 8 | May 13 |
| 16°F | Mar 30 | Apr 3 | Apr 7 | Apr 11 | Apr 15 | Apr 19 | Apr 24 | Apr 28 | May 2 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Aug 22 | Aug 28 | Sep 1 | Sep 4 | Sep 7 | Sep 10 | Sep 12 | Sep 15 | Sep 19 |
| 28°F | Sep 1 | Sep 7 | Sep 10 | Sep 13 | Sep 16 | Sep 19 | Sep 21 | Sep 25 | Sep 30 |
| 24°F | Sep 12 | Sep 16 | Sep 21 | Sep 24 | Sep 27 | Sep 30 | Oct 3 | Oct 6 | Oct 11 |
| 20°F | Sep 23 | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 14 | Oct 18 | Oct 23 |
| 16°F | Oct 3 | Oct 9 | Oct 13 | Oct 16 | Oct 18 | Oct 22 | Oct 25 | Oct 29 | Nov 2 |
Freeze probabilities 1991–2020 at Saratoga 4N, WY, 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 82331 →Compare Saratoga with another place →
Compared with the next station
The nearest other station, Rawlins 1N, WY, 34 miles northwest of Saratoga, has a last frost 26 days earlier (May 17), a first frost 25 days later (October 2), a season 55 days longer.
When it snows in Saratoga, Wyoming
The first measurable snow (0.1 inch or more) in Saratoga usually arrives around October 9, and the last of the season around April 26. Those are the middle dates across the winters of 1991–2020 at Saratoga, WY, 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 47 days after the last snow.
Planting calendar for 82331
| When | What to do |
|---|---|
| April 3 – April 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 17 – May 1 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 15 – May 29 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 12 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 15 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 24 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 7 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 82331 is 3 miles from Saratoga 4N, WY, which stands at 6,801 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82331 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°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.