USDA Hardiness Zone 6a
Frost Dates for 62677 — Pleasant Plains, Illinois
NOAA 1991–2020 normals from Athens 4SW, IL (594 ft), 7 miles northeast.
Updated
In Pleasant Plains, the last spring frost (32°F) is around April 19 in half of years and has passed by May 4 in nine years out of ten. The first fall frost comes around October 19, as early as October 5 one year in ten, leaving a typical freeze-free season of 181 days (NOAA, Athens 4SW, IL).
- Last spring frost
- April 19
- First fall frost
- October 19
- Growing season
- 181 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- December 1
- Last snow
- March 16
- Winters with snow
- 100%
- Snow per year
- 21.8"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Pleasant Plains
Half of springs at Athens 4SW, IL see their last 32°F night by April 19; only one in ten is past it by April 6, and one in ten still has one after May 4. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 29 20%, and after May 4 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 54% of the 158 Illinois stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 19 in half of years, as early as October 5 one year in ten, and holds off past October 31 one year in ten. A hard freeze of 28°F follows 11 days later, around October 30; in spring the one-in-ten date for 28°F is April 23, 11 days before the 32°F one. The freeze-free season lasts 181 days in a typical year, shorter than at 57% of the 158 Illinois stations; it reaches 201 days one year in ten and falls short of 159 one year in ten. On average 121 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 11 days longer, to about April 30, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 2 and March 8.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 2 | May 6 | May 9 | May 14 |
| 32°F | Apr 6 | Apr 10 | Apr 14 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 29 | May 4 |
| 28°F | Mar 24 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 23 |
| 24°F | Mar 11 | Mar 17 | Mar 21 | Mar 25 | Mar 30 | Apr 1 | Apr 3 | Apr 7 | Apr 12 |
| 20°F | Feb 28 | Mar 6 | Mar 10 | Mar 14 | Mar 17 | Mar 20 | Mar 24 | Mar 29 | Apr 2 |
| 16°F | Feb 17 | Feb 25 | Mar 1 | Mar 4 | Mar 8 | Mar 11 | Mar 14 | Mar 19 | Mar 25 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 25 | Sep 30 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 22 |
| 32°F | Oct 5 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 31 |
| 28°F | Oct 14 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 8 | Nov 17 |
| 24°F | Oct 28 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 15 | Nov 19 | Nov 24 | Nov 30 |
| 20°F | Nov 6 | Nov 10 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 5 | Dec 10 |
| 16°F | Nov 13 | Nov 19 | Nov 25 | Nov 29 | Dec 2 | Dec 5 | Dec 9 | Dec 14 | Dec 20 |
Freeze probabilities 1991–2020 at Athens 4SW, IL, 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 62677 →Compare Pleasant Plains with another place →
Weather by month in Pleasant Plains
July is the warmest month at Athens 4SW, IL, averaging 85°F by day and 64°F at night; January is the coldest at 35°F and 18°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 16% of years.
Warmth for growing adds up to 3,409 growing degree days a year (base 50°F), fewer than at 56% of the 158 Illinois stations. 36% of them (1,231) have built up by the end of June, and July adds the most, 758. Precipitation totals 38.5 inches a year, most in May (4.5") and least in February (2.0"); May to September bring 49% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 35 | 18 | 2.2 | 100% | 27 | 2 |
| Feb | 40 | 21 | 2.0 | 100% | 25 | 6 |
| Mar | 52 | 30 | 2.7 | 100% | 18 | 40 |
| Apr | 64 | 40 | 3.9 | 95% | 5 | 153 |
| May | 74 | 51 | 4.5 | 16% | <1 | 393 |
| Jun | 81 | 61 | 4.2 | 0% | 0 | 637 |
| Jul | 85 | 64 | 3.7 | 0% | 0 | 758 |
| Aug | 83 | 62 | 3.3 | 0% | 0 | 697 |
| Sep | 78 | 54 | 3.2 | 5% | 0 | 484 |
| Oct | 66 | 43 | 3.4 | 91% | 4 | 189 |
| Nov | 53 | 33 | 3.1 | 100% | 15 | 45 |
| Dec | 40 | 23 | 2.3 | 100% | 26 | 6 |
Monthly normals 1991–2020 at Athens 4SW, IL (594 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, Springfield Capital Airport, IL, 10 miles east of Pleasant Plains, has a last frost 5 days earlier (April 14), a first frost 1 day later (October 20), a season 6 days longer.
When it snows in Pleasant Plains, Illinois
The first measurable snow (0.1 inch or more) in Pleasant Plains usually arrives around December 1, and the last of the season around March 16. Those are the middle dates across the winters of 1991–2020 at Springfield Capital Airport, IL, 10.4 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 34 days after the last snow.
Planting calendar for 62677
| When | What to do |
|---|---|
| February 8 – February 22 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 22 – March 8 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 22 – April 5 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 19 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 27 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 5 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 19 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 62677 is 7 miles from Athens 4SW, IL, which stands at 594 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 62613 (Athens). The 2023 USDA Plant Hardiness Zone Map lists ZIP 62677 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°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.