USDA Hardiness Zone 5a
Frost Dates for 51445 — Ida Grove, Iowa
NOAA 1991–2020 normals from Ida Grove 5NW, IA (1,320 ft), 5 miles northwest.
Updated
In Ida Grove, the last spring frost (32°F) is around April 27 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 12, as early as September 27 one year in ten, leaving a typical freeze-free season of 167 days (NOAA, Ida Grove 5NW, IA).
- Last spring frost
- April 27
- First fall frost
- October 12
- Growing season
- 167 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
- November 16
- Last snow
- March 21
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
17 of 17 observed
NOAA normal
Frost risk by date in Ida Grove
Half of springs at Ida Grove 5NW, IA see their last 32°F night by April 27; only one in ten is past it by April 12, and one in ten still has one after May 11. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 5 20%, and after May 11 10%. The 14 days between the even-odds date and the one-in-ten date is wider than at 58% of the 132 Iowa stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 12 in half of years, as early as September 27 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 9 days later, around October 21; in spring the one-in-ten date for 28°F is May 1, 10 days before the 32°F one. The freeze-free season lasts 167 days in a typical year, longer than at 60% of the 132 Iowa stations; it reaches 186 days one year in ten and falls short of 147 one year in ten. On average 155 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 5, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 15 and March 21.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 24 | Apr 28 | May 1 | May 3 | May 5 | May 8 | May 11 | May 15 | May 21 |
| 32°F | Apr 12 | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 2 | May 5 | May 11 |
| 28°F | Apr 2 | Apr 6 | Apr 9 | Apr 13 | Apr 17 | Apr 20 | Apr 23 | Apr 27 | May 1 |
| 24°F | Mar 23 | Mar 30 | Apr 2 | Apr 5 | Apr 7 | Apr 9 | Apr 12 | Apr 16 | Apr 21 |
| 20°F | Mar 12 | Mar 19 | Mar 24 | Mar 27 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 15 |
| 16°F | Mar 4 | Mar 10 | Mar 14 | Mar 17 | Mar 21 | Mar 24 | Mar 28 | Mar 31 | Apr 5 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 20 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 16 |
| 32°F | Sep 27 | Oct 1 | Oct 5 | Oct 9 | Oct 12 | Oct 15 | Oct 17 | Oct 20 | Oct 24 |
| 28°F | Oct 4 | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 2 |
| 24°F | Oct 17 | Oct 22 | Oct 25 | Oct 28 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 13 |
| 20°F | Oct 26 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 9 | Nov 13 | Nov 17 | Nov 23 |
| 16°F | Nov 1 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 22 | Nov 26 | Dec 1 |
Freeze probabilities 1991–2020 at Ida Grove 5NW, 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 51445 →Compare Ida Grove with another place →
Weather by month in Ida Grove
July is the warmest month at Ida Grove 5NW, IA, averaging 84°F by day and 63°F at night; January is the coldest at 27°F and 9°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 35% of years.
Warmth for growing adds up to 2,992 growing degree days a year (base 50°F), fewer than at 52% of the 132 Iowa stations. 35% of them (1,035) have built up by the end of June, and July adds the most, 731.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 27 | 9 | 100% | 31 | 0 |
| Feb | 32 | 13 | 100% | 27 | 1 |
| Mar | 45 | 25 | 100% | 24 | 17 |
| Apr | 59 | 36 | 100% | 10 | 92 |
| May | 70 | 49 | 35% | 1 | 315 |
| Jun | 81 | 60 | 0% | 0 | 611 |
| Jul | 84 | 63 | 0% | 0 | 731 |
| Aug | 82 | 61 | 0% | 0 | 657 |
| Sep | 75 | 52 | 18% | 1 | 414 |
| Oct | 62 | 39 | 98% | 8 | 136 |
| Nov | 46 | 26 | 100% | 23 | 19 |
| Dec | 32 | 15 | 100% | 30 | 1 |
Monthly normals 1991–2020 at Ida Grove 5NW, IA (1,320 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, Denison, IA, 22 miles south of Ida Grove, has the same 50% last-frost date, a first frost 1 day earlier (October 11), a season 1 day shorter.
When it snows in Ida Grove, Iowa
The first measurable snow (0.1 inch or more) in Ida Grove usually arrives around November 16, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Ida Grove 5NW, IA, 4.9 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 37 days after the last snow.
Planting calendar for 51445
| When | What to do |
|---|---|
| February 16 – March 2 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 2 – March 16 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 30 – April 13 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 27 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 20 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 28 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 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 51445 is 5 miles from Ida Grove 5NW, IA, which stands at 1,320 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 51445 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.