USDA Hardiness Zone 5a
Frost Dates for 51334 — Estherville, Iowa
NOAA 1991–2020 normals from Estherville 4E, IA (1,320 ft), 3 miles east.
Updated
In Estherville, the last spring frost (32°F) is around May 2 in half of years and has passed by May 14 in nine years out of ten. The first fall frost comes around October 3, as early as September 20 one year in ten, leaving a typical freeze-free season of 153 days (NOAA, Estherville 4E, IA).
- Last spring frost
- May 2
- First fall frost
- October 3
- Growing season
- 153 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 15
- Last snow
- March 15
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
27 of 27 observed
NOAA normal
Frost risk by date in Estherville
Half of springs at Estherville 4E, IA see their last 32°F night by May 2; only one in ten is past it by April 18, and one in ten still has one after May 14. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 10 20%, and after May 14 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 132 Iowa stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 3 in half of years, as early as September 20 one year in ten, and holds off past October 17 one year in ten. A hard freeze of 28°F follows 11 days later, around October 14; in spring the one-in-ten date for 28°F is May 5, 9 days before the 32°F one. The freeze-free season lasts 153 days in a typical year, shorter than at 89% of the 132 Iowa stations; it reaches 171 days one year in ten and falls short of 134 one year in ten. On average 166 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 10, and return around September 25. Severe cold of 16°F or below comes every winter, usually between November 10 and March 28.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 29 | May 2 | May 5 | May 8 | May 10 | May 13 | May 15 | May 19 | May 24 |
| 32°F | Apr 18 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 4 | May 7 | May 10 | May 14 |
| 28°F | Apr 7 | Apr 12 | Apr 16 | Apr 18 | Apr 22 | Apr 25 | Apr 28 | May 1 | May 5 |
| 24°F | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 18 | Apr 21 | Apr 26 |
| 20°F | Mar 17 | Mar 24 | Mar 29 | Apr 1 | Apr 3 | Apr 6 | Apr 10 | Apr 13 | Apr 19 |
| 16°F | Mar 10 | Mar 14 | Mar 19 | Mar 23 | Mar 28 | Mar 31 | Apr 2 | Apr 7 | Apr 13 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 12 | Sep 17 | Sep 20 | Sep 22 | Sep 25 | Sep 27 | Sep 29 | Oct 2 | Oct 7 |
| 32°F | Sep 20 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 5 | Oct 9 | Oct 12 | Oct 17 |
| 28°F | Sep 30 | Oct 4 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 27 |
| 24°F | Oct 11 | Oct 16 | Oct 20 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 2 | Nov 7 |
| 20°F | Oct 21 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 13 | Nov 18 |
| 16°F | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 21 | Nov 28 |
Freeze probabilities 1991–2020 at Estherville 4E, 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 51334 →Compare Estherville with another place →
Weather by month in Estherville
July is the warmest month at Estherville 4E, IA, averaging 83°F by day and 60°F at night; January is the coldest at 24°F and 5°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 57% of years.
Warmth for growing adds up to 2,560 growing degree days a year (base 50°F), fewer than at 97% of the 132 Iowa stations. 34% of them (871) have built up by the end of June, and July adds the most, 660.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 24 | 5 | 100% | 31 | 0 |
| Feb | 28 | 10 | 100% | 27 | 0 |
| Mar | 41 | 22 | 100% | 26 | 8 |
| Apr | 57 | 33 | 100% | 13 | 58 |
| May | 69 | 46 | 57% | 2 | 262 |
| Jun | 79 | 57 | 0% | 0 | 543 |
| Jul | 83 | 60 | 0% | 0 | 660 |
| Aug | 80 | 57 | 0% | 0 | 575 |
| Sep | 74 | 48 | 39% | 1 | 344 |
| Oct | 60 | 36 | 99% | 12 | 99 |
| Nov | 43 | 23 | 100% | 25 | 11 |
| Dec | 29 | 11 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Estherville 4E, 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, Spirit Lake, IA, 16 miles west of Estherville, has a last frost 4 days earlier (April 28), a first frost 8 days later (October 11), a season 11 days longer.
When it snows in Estherville, Iowa
The first measurable snow (0.1 inch or more) in Estherville usually arrives around November 15, and the last of the season around March 15. Those are the middle dates across the winters of 1991–2020 at Estherville 4E, IA, 3.4 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 48 days after the last snow.
Planting calendar for 51334
| When | What to do |
|---|---|
| February 21 – March 7 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 7 – March 21 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 4 – April 18 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 19 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 3 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 51334 is 3 miles from Estherville 4E, 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 51334 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.