USDA Hardiness Zone 5b
Frost Dates for 50801 — Creston, Iowa
NOAA 1991–2020 normals from Creston 2 SW, IA (1,296 ft), 2 miles south.
Updated
In Creston, the last spring frost (32°F) is around April 28 in half of years and has passed by May 9 in nine years out of ten. The first fall frost comes around October 11, as early as September 24 one year in ten, leaving a typical freeze-free season of 164 days (NOAA, Creston 2 SW, IA).
- Last spring frost
- April 28
- First fall frost
- October 11
- 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 26
- Last snow
- March 12
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
28 of 28 observed
NOAA normal
Frost risk by date in Creston
Half of springs at Creston 2 SW, IA see their last 32°F night by April 28; only one in ten is past it by April 14, and one in ten still has one after May 9. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 6 20%, and after May 9 10%. The 11 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 132 Iowa stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 11 in half of years, as early as September 24 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 12 days later, around October 23; in spring the one-in-ten date for 28°F is May 2, 7 days before the 32°F one. The freeze-free season lasts 164 days in a typical year, shorter than at 52% of the 132 Iowa stations; it reaches 183 days one year in ten and falls short of 144 one year in ten. On average 145 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 8 days longer, to about May 6, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 14 and March 20.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 23 | Apr 29 | May 2 | May 4 | May 6 | May 9 | May 10 | May 14 | May 19 |
| 32°F | Apr 14 | Apr 18 | Apr 22 | Apr 25 | Apr 28 | May 1 | May 3 | May 6 | May 9 |
| 28°F | Apr 5 | Apr 8 | Apr 12 | Apr 15 | Apr 17 | Apr 21 | Apr 23 | Apr 28 | May 2 |
| 24°F | Mar 25 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 10 | Apr 14 | Apr 17 | Apr 23 |
| 20°F | Mar 11 | Mar 19 | Mar 24 | Mar 28 | Mar 31 | Apr 3 | Apr 6 | Apr 9 | Apr 15 |
| 16°F | Mar 4 | Mar 8 | Mar 12 | Mar 15 | Mar 20 | Mar 24 | Mar 29 | Apr 1 | Apr 7 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 16 | Sep 21 | Sep 25 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 15 |
| 32°F | Sep 24 | Sep 30 | Oct 4 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 21 | Oct 26 |
| 28°F | Oct 5 | Oct 12 | Oct 16 | Oct 19 | Oct 23 | Oct 25 | Oct 27 | Oct 31 | Nov 4 |
| 24°F | Oct 17 | Oct 22 | Oct 25 | Oct 29 | Oct 31 | Nov 2 | Nov 4 | Nov 8 | Nov 13 |
| 20°F | Oct 25 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 9 | Nov 12 | Nov 16 | Nov 22 |
| 16°F | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 18 | Nov 21 | Nov 26 | Dec 1 |
Freeze probabilities 1991–2020 at Creston 2 SW, IA, 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 50801 →Compare Creston with another place →
Weather by month in Creston
July is the warmest month at Creston 2 SW, IA, averaging 85°F by day and 63°F at night; January is the coldest at 31°F and 11°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August 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 3,075 growing degree days a year (base 50°F), more than at 58% of the 132 Iowa stations. 34% of them (1,057) have built up by the end of June, and July adds the most, 742.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 31 | 11 | 100% | 30 | 0 |
| Feb | 35 | 14 | 100% | 26 | 1 |
| Mar | 49 | 26 | 100% | 23 | 26 |
| Apr | 61 | 36 | 100% | 9 | 98 |
| May | 71 | 49 | 40% | 1 | 328 |
| Jun | 81 | 59 | 0% | 0 | 605 |
| Jul | 85 | 63 | 0% | 0 | 742 |
| Aug | 83 | 61 | 0% | 0 | 677 |
| Sep | 76 | 52 | 20% | <1 | 426 |
| Oct | 64 | 39 | 96% | 7 | 153 |
| Nov | 48 | 26 | 100% | 20 | 20 |
| Dec | 36 | 16 | 100% | 29 | 1 |
Monthly normals 1991–2020 at Creston 2 SW, IA (1,296 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, Greenfield, IA, 16 miles north of Creston, has a last frost 3 days earlier (April 25), a first frost 1 day later (October 12), a season 6 days longer.
When it snows in Creston, Iowa
The first measurable snow (0.1 inch or more) in Creston usually arrives around November 26, and the last of the season around March 12. Those are the middle dates across the winters of 1991–2020 at Creston 2 SW, IA, 2.4 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 50801
| 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 19 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 27 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 11 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 50801 is 2 miles from Creston 2 SW, IA, which stands at 1,296 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 50801 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.