USDA Hardiness Zone 5b
Frost Dates for 83210 — Aberdeen, Idaho
NOAA 1991–2020 normals from Aberdeen Exp Stn, ID (4,405 ft), 1 miles south.
Updated
In Aberdeen, the last spring frost (32°F) is around May 21 in half of years and has passed by June 13 in nine years out of ten. The first fall frost comes around September 20, as early as September 2 one year in ten, leaving a typical freeze-free season of 118 days (NOAA, Aberdeen Exp Stn, ID).
- Last spring frost
- May 21
- First fall frost
- September 20
- Growing season
- 118 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 25
- Last snow
- March 18
- Winters with snow
- 100%
- Snow per year
- 25.2"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Aberdeen
Half of springs at Aberdeen Exp Stn, ID see their last 32°F night by May 21; only one in ten is past it by May 4, and one in ten still has one after June 13. Planting tender crops after May 31 leaves a 30% risk of a frost on them, after June 5 20%, and after June 13 10%. The 23 days between the even-odds date and the one-in-ten date is wider than at 87% of the 67 Idaho stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by September 20 in half of years, as early as September 2 one year in ten, and holds off past October 4 one year in ten. A hard freeze of 28°F follows 11 days later, around October 1; in spring the one-in-ten date for 28°F is May 17, 27 days before the 32°F one. The freeze-free season lasts 118 days in a typical year, shorter than at 82% of the 67 Idaho stations; it reaches 141 days one year in ten and falls short of 91 one year in ten. On average 196 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 22 days longer, to about June 12, and return around September 5. Severe cold of 16°F or below comes every winter, usually between November 6 and March 13.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 23 | May 31 | Jun 4 | Jun 9 | Jun 12 | Jun 16 | Jun 19 | Jun 23 | Jun 28 |
| 32°F | May 4 | May 9 | May 13 | May 16 | May 21 | May 26 | May 31 | Jun 5 | Jun 13 |
| 28°F | Apr 20 | Apr 26 | Apr 28 | Apr 30 | May 3 | May 5 | May 8 | May 12 | May 17 |
| 24°F | Apr 6 | Apr 11 | Apr 15 | Apr 18 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 5 |
| 20°F | Mar 14 | Mar 23 | Mar 31 | Apr 4 | Apr 7 | Apr 12 | Apr 16 | Apr 20 | Apr 25 |
| 16°F | Feb 27 | Mar 4 | Mar 7 | Mar 10 | Mar 13 | Mar 18 | Mar 30 | Apr 4 | Apr 10 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 21 | Aug 27 | Aug 31 | Sep 3 | Sep 5 | Sep 9 | Sep 13 | Sep 17 | Sep 22 |
| 32°F | Sep 2 | Sep 8 | Sep 13 | Sep 17 | Sep 20 | Sep 22 | Sep 26 | Sep 29 | Oct 4 |
| 28°F | Sep 15 | Sep 20 | Sep 24 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 12 | Oct 17 |
| 24°F | Sep 27 | Oct 3 | Oct 6 | Oct 11 | Oct 14 | Oct 17 | Oct 21 | Oct 24 | Oct 31 |
| 20°F | Oct 11 | Oct 17 | Oct 21 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 6 | Nov 13 |
| 16°F | Oct 22 | Oct 27 | Nov 1 | Nov 2 | Nov 6 | Nov 10 | Nov 15 | Nov 20 | Nov 25 |
Freeze probabilities 1991–2020 at Aberdeen Exp Stn, ID, 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 83210 →Compare Aberdeen with another place →
Weather by month in Aberdeen
July is the warmest month at Aberdeen Exp Stn, ID, averaging 87°F by day and 51°F at night; January is the coldest at 32°F and 14°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 29% of years.
Warmth for growing adds up to 2,006 growing degree days a year (base 50°F), fewer than at 61% of the 67 Idaho stations. 27% of them (542) have built up by the end of June, and July adds the most, 592. Precipitation totals 9.7 inches a year, most in May (1.2") and least in July (0.4"); May to September bring 39% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 32 | 14 | 0.9 | 100% | 31 | 0 |
| Feb | 37 | 17 | 0.6 | 100% | 27 | 0 |
| Mar | 48 | 26 | 0.9 | 100% | 28 | 2 |
| Apr | 58 | 31 | 0.9 | 100% | 20 | 27 |
| May | 68 | 40 | 1.2 | 94% | 6 | 165 |
| Jun | 77 | 46 | 1.0 | 29% | 1 | 347 |
| Jul | 87 | 51 | 0.4 | 0% | 0 | 592 |
| Aug | 87 | 49 | 0.4 | 7% | <1 | 551 |
| Sep | 76 | 40 | 0.8 | 81% | 5 | 271 |
| Oct | 61 | 30 | 0.9 | 100% | 21 | 49 |
| Nov | 45 | 22 | 0.7 | 100% | 27 | 2 |
| Dec | 33 | 15 | 1.0 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Aberdeen Exp Stn, ID (4,405 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, American Falls, ID, 12 miles south of Aberdeen, has a last frost 17 days earlier (May 4), a first frost 18 days later (October 8), a season 37 days longer.
When it snows in Aberdeen, Idaho
The first measurable snow (0.1 inch or more) in Aberdeen usually arrives around November 25, and the last of the season around March 18. Those are the middle dates across the winters of 1991–2020 at Aberdeen Exp Stn, ID, 1.3 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 64 days after the last snow.
Planting calendar for 83210
| When | What to do |
|---|---|
| March 12 – March 26 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 26 – April 9 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 23 – May 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 28 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 6 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 20 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 83210 is 1 mile from Aberdeen Exp Stn, ID, which stands at 4,405 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 83210 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.