USDA Hardiness Zone 6a
Frost Dates for 61910 — Arcola, Illinois
NOAA 1991–2020 normals from Tuscola, IL (651 ft), 8 miles north.
Updated
In Arcola, the last spring frost (32°F) is around April 15 in half of years and has passed by May 1 in nine years out of ten. The first fall frost comes around October 20, as early as October 7 one year in ten, leaving a typical freeze-free season of 188 days (NOAA, Tuscola, IL).
- Last spring frost
- April 15
- First fall frost
- October 20
- Growing season
- 188 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 8
- Winters with snow
- 100%
- Snow per year
- 16.9"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Arcola
Half of springs at Tuscola, IL see their last 32°F night by April 15; only one in ten is past it by April 3, and one in ten still has one after May 1. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 25 20%, and after May 1 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 22% of the 158 Illinois stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 20 in half of years, as early as October 7 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 11 days later, around October 31; in spring the one-in-ten date for 28°F is April 19, 12 days before the 32°F one. The freeze-free season lasts 188 days in a typical year, longer than at 58% of the 158 Illinois stations; it reaches 207 days one year in ten and falls short of 167 one year in ten. On average 117 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 12 days longer, to about April 27, and return around October 11. Severe cold of 16°F or below comes every winter, usually between November 30 and March 8.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 13 | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 3 | May 8 | May 13 |
| 32°F | Apr 3 | Apr 6 | Apr 10 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 25 | May 1 |
| 28°F | Mar 19 | Mar 27 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 13 | Apr 19 |
| 24°F | Mar 10 | Mar 15 | Mar 19 | Mar 23 | Mar 26 | Mar 29 | Mar 31 | Apr 3 | Apr 8 |
| 20°F | Feb 28 | Mar 5 | Mar 10 | Mar 13 | Mar 16 | Mar 19 | Mar 22 | Mar 26 | Mar 31 |
| 16°F | Feb 17 | Feb 24 | Mar 1 | Mar 4 | Mar 8 | Mar 11 | Mar 14 | Mar 17 | Mar 22 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 5 | Oct 7 | Oct 11 | Oct 13 | Oct 16 | Oct 18 | Oct 22 |
| 32°F | Oct 7 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Nov 1 |
| 28°F | Oct 18 | Oct 23 | Oct 26 | Oct 29 | Oct 31 | Nov 1 | Nov 4 | Nov 8 | Nov 14 |
| 24°F | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 12 | Nov 17 | Nov 21 | Nov 27 |
| 20°F | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 27 | Dec 2 | Dec 9 |
| 16°F | Nov 9 | Nov 17 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 8 | Dec 14 | Dec 21 |
Freeze probabilities 1991–2020 at Tuscola, 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 61910 →Compare Arcola with another place →
Weather by month in Arcola
July is the warmest month at Tuscola, IL, averaging 85°F by day and 65°F at night; January is the coldest at 34°F and 18°F. A freezing night is all but certain in every month from November 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 12% of years.
Warmth for growing adds up to 3,578 growing degree days a year (base 50°F), more than at 58% of the 158 Illinois stations. 37% of them (1,312) have built up by the end of June, and July adds the most, 780. Precipitation totals 40.6 inches a year, most in June (4.8") and least in February (2.1"); May to September bring 48% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 34 | 18 | 2.4 | 100% | 27 | 2 |
| Feb | 39 | 21 | 2.1 | 100% | 23 | 4 |
| Mar | 50 | 31 | 2.9 | 100% | 19 | 42 |
| Apr | 64 | 42 | 4.5 | 93% | 5 | 159 |
| May | 74 | 53 | 4.2 | 12% | <1 | 428 |
| Jun | 82 | 63 | 4.8 | 0% | 0 | 678 |
| Jul | 85 | 65 | 4.4 | 0% | 0 | 780 |
| Aug | 84 | 63 | 3.0 | 0% | 0 | 728 |
| Sep | 79 | 55 | 3.1 | 4% | <1 | 510 |
| Oct | 66 | 43 | 3.3 | 88% | 4 | 206 |
| Nov | 51 | 32 | 3.4 | 100% | 16 | 39 |
| Dec | 39 | 24 | 2.5 | 100% | 24 | 4 |
Monthly normals 1991–2020 at Tuscola, IL (651 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, Mattoon, IL, 14 miles south of Arcola, has a last frost 4 days earlier (April 11), a first frost 9 days later (October 29), a season 11 days longer.
When it snows in Arcola, Illinois
The first measurable snow (0.1 inch or more) in Arcola usually arrives around December 1, and the last of the season around March 8. Those are the middle dates across the winters of 1991–2020 at Tuscola, IL, 8.2 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 38 days after the last snow.
Planting calendar for 61910
| When | What to do |
|---|---|
| February 4 – February 18 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 18 – March 4 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 18 – April 1 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 15 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 28 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 6 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 20 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 61910 is 8 miles from Tuscola, IL, which stands at 651 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 61953 (Tuscola). The 2023 USDA Plant Hardiness Zone Map lists ZIP 61910 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.