USDA Hardiness Zone 5b
Frost Dates for 50207 — New Sharon, Iowa
NOAA 1991–2020 normals from Oskaloosa, IA (830 ft), 9 miles south.
Updated
In New Sharon, the last spring frost (32°F) is around April 21 in half of years and has passed by May 4 in nine years out of ten. The first fall frost comes around October 16, as early as September 29 one year in ten, leaving a typical freeze-free season of 176 days (NOAA, Oskaloosa, IA).
- Last spring frost
- April 21
- First fall frost
- October 16
- Growing season
- 176 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
- December 9
- Last snow
- March 6
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
24 of 24 observed
NOAA normal
Frost risk by date in New Sharon
Half of springs at Oskaloosa, IA see their last 32°F night by April 21; only one in ten is past it by April 8, and one in ten still has one after May 4. Planting tender crops after April 28 leaves a 30% risk of a frost on them, after May 1 20%, and after May 4 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 42% of the 132 Iowa stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 16 in half of years, as early as September 29 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 27; in spring the one-in-ten date for 28°F is April 26, 8 days before the 32°F one. The freeze-free season lasts 176 days in a typical year, longer than at 83% of the 132 Iowa stations; it reaches 196 days one year in ten and falls short of 155 one year in ten. On average 144 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 10 days longer, to about May 1, and return around October 4. Severe cold of 16°F or below comes every winter, usually between November 21 and March 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 18 | Apr 23 | Apr 26 | Apr 29 | May 1 | May 4 | May 6 | May 9 | May 14 |
| 32°F | Apr 8 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 24 | Apr 28 | May 1 | May 4 |
| 28°F | Mar 29 | Apr 3 | Apr 6 | Apr 9 | Apr 11 | Apr 14 | Apr 16 | Apr 21 | Apr 26 |
| 24°F | Mar 17 | Mar 23 | Mar 28 | Mar 31 | Apr 3 | Apr 5 | Apr 8 | Apr 12 | Apr 17 |
| 20°F | Mar 7 | Mar 13 | Mar 17 | Mar 20 | Mar 23 | Mar 27 | Mar 31 | Apr 3 | Apr 8 |
| 16°F | Feb 28 | Mar 4 | Mar 7 | Mar 11 | Mar 14 | Mar 17 | Mar 20 | Mar 25 | Mar 31 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 21 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 14 | Oct 19 |
| 32°F | Sep 29 | Oct 5 | Oct 9 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 29 |
| 28°F | Oct 10 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 8 |
| 24°F | Oct 23 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 9 | Nov 13 | Nov 19 |
| 20°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 30 |
| 16°F | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 21 | Nov 25 | Nov 28 | Dec 1 | Dec 7 |
Freeze probabilities 1991–2020 at Oskaloosa, 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 50207 →Compare New Sharon with another place →
Weather by month in New Sharon
July is the warmest month at Oskaloosa, IA, averaging 86°F by day and 65°F at night; January is the coldest at 31°F and 12°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 22% of years.
Warmth for growing adds up to 3,296 growing degree days a year (base 50°F), more than at 85% of the 132 Iowa stations. 35% of them (1,153) have built up by the end of June, and July adds the most, 780. Precipitation totals 38.9 inches a year, most in June (5.2") and least in December (1.4"); May to September bring 59% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 31 | 12 | 1.8 | 100% | 30 | 0 |
| Feb | 36 | 16 | 1.7 | 100% | 26 | 2 |
| Mar | 49 | 27 | 2.2 | 100% | 22 | 32 |
| Apr | 62 | 38 | 3.9 | 98% | 9 | 119 |
| May | 72 | 51 | 4.7 | 22% | 1 | 365 |
| Jun | 82 | 61 | 5.2 | 0% | 0 | 634 |
| Jul | 86 | 65 | 4.4 | 0% | 0 | 780 |
| Aug | 84 | 62 | 5.1 | 0% | 0 | 710 |
| Sep | 77 | 53 | 3.6 | 13% | <1 | 459 |
| Oct | 65 | 41 | 2.7 | 94% | 7 | 170 |
| Nov | 49 | 29 | 2.2 | 100% | 20 | 25 |
| Dec | 36 | 18 | 1.4 | 100% | 29 | 1 |
Monthly normals 1991–2020 at Oskaloosa, IA (830 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, Grinnell 3 SW, IA, 20 miles north of New Sharon, has a last frost 12 days later (May 3), a first frost 10 days earlier (October 6), a season 21 days shorter.
When it snows in New Sharon, Iowa
The first measurable snow (0.1 inch or more) in New Sharon usually arrives around December 9, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Oskaloosa, IA, 8.5 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 46 days after the last snow.
Planting calendar for 50207
| When | What to do |
|---|---|
| February 10 – February 24 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 24 – March 10 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 24 – April 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 24 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 2 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 16 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 50207 is 9 miles from Oskaloosa, IA, which stands at 830 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 52577 (Oskaloosa). The 2023 USDA Plant Hardiness Zone Map lists ZIP 50207 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.