USDA Hardiness Zone 5a
Frost Dates for 50421 — Belmond, Iowa
NOAA 1991–2020 normals from Clarion, IA (1,156 ft), 10 miles southwest.
Updated
In Belmond, the last spring frost (32°F) is around April 30 in half of years and has passed by May 12 in nine years out of ten. The first fall frost comes around October 10, as early as September 27 one year in ten, leaving a typical freeze-free season of 162 days (NOAA, Clarion, IA).
- Last spring frost
- April 30
- First fall frost
- October 10
- Growing season
- 162 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 13
- Last snow
- March 29
- Winters with snow
- 100%
- Snow per year
- 31.1"
median, 1991–2020
median, 1991–2020
20 of 20 observed
NOAA normal
Frost risk by date in Belmond
Half of springs at Clarion, IA see their last 32°F night by April 30; only one in ten is past it by April 17, and one in ten still has one after May 12. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 8 20%, and after May 12 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 10 in half of years, as early as September 27 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 9 days later, around October 19; in spring the one-in-ten date for 28°F is May 3, 9 days before the 32°F one. The freeze-free season lasts 162 days in a typical year, shorter than at 61% of the 132 Iowa stations; it reaches 179 days one year in ten and falls short of 142 one year in ten. On average 161 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 8, 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 27 | May 1 | May 3 | May 5 | May 8 | May 10 | May 12 | May 16 | May 21 |
| 32°F | Apr 17 | Apr 20 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 4 | May 8 | May 12 |
| 28°F | Apr 4 | Apr 10 | Apr 14 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 29 | May 3 |
| 24°F | Mar 24 | Apr 1 | Apr 4 | Apr 7 | Apr 10 | Apr 12 | Apr 16 | Apr 20 | Apr 26 |
| 20°F | Mar 13 | Mar 19 | Mar 23 | Mar 28 | Apr 1 | Apr 4 | Apr 7 | Apr 10 | Apr 17 |
| 16°F | Mar 4 | Mar 9 | Mar 13 | Mar 16 | Mar 20 | Mar 24 | Mar 28 | Apr 1 | Apr 7 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 12 |
| 32°F | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 21 |
| 28°F | Oct 4 | Oct 10 | Oct 14 | Oct 17 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Oct 31 |
| 24°F | Oct 16 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 6 | Nov 10 |
| 20°F | Oct 25 | Oct 31 | Nov 2 | Nov 4 | Nov 6 | Nov 9 | Nov 11 | Nov 15 | Nov 20 |
| 16°F | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 14 | Nov 17 | Nov 19 | Nov 23 | Nov 29 |
Freeze probabilities 1991–2020 at Clarion, 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 50421 →Compare Belmond with another place →
Weather by month in Belmond
July is the warmest month at Clarion, IA, averaging 85°F by day and 62°F at night; January is the coldest at 26°F and 6°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 46% of years.
Warmth for growing adds up to 2,971 growing degree days a year (base 50°F), fewer than at 55% of the 132 Iowa stations. 35% of them (1,025) have built up by the end of June, and July adds the most, 727. Precipitation totals 34.2 inches a year, most in June (5.8") and least in January (0.7"); May to September bring 64% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 26 | 6 | 0.7 | 100% | 31 | 0 |
| Feb | 31 | 11 | 0.9 | 100% | 27 | 1 |
| Mar | 44 | 25 | 2.0 | 100% | 25 | 15 |
| Apr | 59 | 35 | 3.8 | 100% | 13 | 81 |
| May | 72 | 48 | 4.8 | 46% | 1 | 319 |
| Jun | 82 | 59 | 5.8 | 0% | 0 | 609 |
| Jul | 85 | 62 | 4.0 | 0% | 0 | 727 |
| Aug | 82 | 60 | 4.1 | 0% | 0 | 654 |
| Sep | 76 | 51 | 3.1 | 19% | 1 | 415 |
| Oct | 63 | 38 | 2.3 | 99% | 10 | 136 |
| Nov | 45 | 25 | 1.5 | 100% | 24 | 14 |
| Dec | 31 | 13 | 1.2 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Clarion, IA (1,156 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, Britt 3E, IA, 19 miles north of Belmond, has a last frost 1 day earlier (April 29), a first frost 3 days earlier (October 7), a season 1 day shorter.
When it snows in Belmond, Iowa
The first measurable snow (0.1 inch or more) in Belmond usually arrives around November 13, and the last of the season around March 29. Those are the middle dates across the winters of 1991–2020 at Clarion, IA, 10.3 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 32 days after the last snow.
Planting calendar for 50421
| When | What to do |
|---|---|
| February 19 – March 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 5 – March 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 2 – April 16 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 30 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 18 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 10 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 50421 is 10 miles from Clarion, IA, which stands at 1,156 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 50533 (Eagle Grove). The 2023 USDA Plant Hardiness Zone Map lists ZIP 50421 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.