USDA Hardiness Zone 5a
Frost Dates for 52045 — Epworth, Iowa
NOAA 1991–2020 normals from Cascade, IA (814 ft), 11 miles south.
Updated
In Epworth, the last spring frost (32°F) is around April 28 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 28 one year in ten, leaving a typical freeze-free season of 164 days (NOAA, Cascade, IA).
- Last spring frost
- April 28
- First fall frost
- October 10
- Growing season
- 164 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
- December 2
- Last snow
- March 24
- Winters with snow
- 100%
- Snow per year
- 31.1"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Epworth
Half of springs at Cascade, IA see their last 32°F night by April 28; only one in ten is past it by April 12, and one in ten still has one after May 12. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 6 20%, and after May 12 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 10 in half of years, as early as September 28 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 10 days later, around October 20; in spring the one-in-ten date for 28°F is May 2, 10 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 184 days one year in ten and falls short of 146 one year in ten. On average 153 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 September 30. Severe cold of 16°F or below comes every winter, usually between November 21 and March 15.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 24 | Apr 29 | May 1 | May 4 | May 6 | May 10 | May 13 | May 16 | May 21 |
| 32°F | Apr 12 | Apr 17 | Apr 21 | Apr 24 | Apr 28 | Apr 30 | May 3 | May 6 | May 12 |
| 28°F | Apr 1 | Apr 6 | Apr 9 | Apr 13 | Apr 15 | Apr 19 | Apr 22 | Apr 28 | May 2 |
| 24°F | Mar 21 | Mar 28 | Mar 31 | Apr 3 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 21 |
| 20°F | Mar 10 | Mar 15 | Mar 19 | Mar 23 | Mar 27 | Mar 31 | Apr 2 | Apr 6 | Apr 12 |
| 16°F | Mar 2 | Mar 6 | Mar 10 | Mar 13 | Mar 15 | Mar 19 | Mar 23 | Mar 28 | Apr 2 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 22 | Sep 25 | Sep 28 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 12 |
| 32°F | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 11 | Oct 14 | Oct 16 | Oct 21 |
| 28°F | Oct 7 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 22 | Oct 24 | Oct 27 | Nov 1 |
| 24°F | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 8 | Nov 13 |
| 20°F | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 22 | Nov 27 |
| 16°F | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 7 |
Freeze probabilities 1991–2020 at Cascade, 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 52045 →Compare Epworth with another place →
Weather by month in Epworth
July is the warmest month at Cascade, IA, averaging 83°F by day and 63°F at night; January is the coldest at 27°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 38% of years.
Warmth for growing adds up to 2,894 growing degree days a year (base 50°F), fewer than at 63% of the 132 Iowa stations. 35% of them (1,010) have built up by the end of June, and July adds the most, 708. Precipitation totals 39.6 inches a year, most in June (6.0") and least in January (1.3"); May to September bring 59% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 27 | 11 | 1.3 | 100% | 30 | 0 |
| Feb | 32 | 15 | 1.5 | 100% | 27 | 0 |
| Mar | 45 | 26 | 2.2 | 100% | 24 | 18 |
| Apr | 59 | 37 | 4.0 | 99% | 10 | 85 |
| May | 70 | 49 | 4.2 | 38% | 1 | 316 |
| Jun | 80 | 60 | 6.0 | 0% | 0 | 591 |
| Jul | 83 | 63 | 4.5 | 0% | 0 | 708 |
| Aug | 81 | 60 | 4.7 | 0% | 0 | 640 |
| Sep | 75 | 51 | 3.8 | 16% | 1 | 398 |
| Oct | 62 | 39 | 3.3 | 98% | 10 | 120 |
| Nov | 46 | 28 | 2.3 | 100% | 21 | 16 |
| Dec | 33 | 18 | 1.8 | 100% | 29 | 1 |
Monthly normals 1991–2020 at Cascade, IA (814 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, Dubuque Regional Airport, IA, 12 miles east of Epworth and 242 feet higher, has the same 50% last-frost date, a first frost 1 day later (October 11), a season 1 day longer.
When it snows in Epworth, Iowa
The first measurable snow (0.1 inch or more) in Epworth usually arrives around December 2, and the last of the season around March 24. Those are the middle dates across the winters of 1991–2020 at Cascade, IA, 11.4 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 35 days after the last snow.
Planting calendar for 52045
| 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 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 52045 is 11 miles from Cascade, IA, which stands at 814 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 52040 (Dyersville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 52045 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.