USDA Hardiness Zone 6a
Frost Dates for 61554 — Pekin, Illinois
NOAA 1991–2020 normals from Peoria Gtr Peoria Airport, IL (650 ft), 7 miles north.
Updated
In Pekin, the last spring frost (32°F) is around April 16 in half of years and has passed by May 4 in nine years out of ten. The first fall frost comes around October 23, as early as October 9 one year in ten, leaving a typical freeze-free season of 189 days (NOAA, Peoria Gtr Peoria Airport, IL).
- Last spring frost
- April 16
- First fall frost
- October 23
- Growing season
- 189 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 20
- Winters with snow
- 100%
- Snow per year
- 26.2"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Pekin
Half of springs at Peoria Gtr Peoria Airport, IL see their last 32°F night by April 16; only one in ten is past it by April 2, and one in ten still has one after May 4. Planting tender crops after April 23 leaves a 30% risk of a frost on them, after April 28 20%, and after May 4 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 92% of the 158 Illinois stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 23 in half of years, as early as October 9 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 10 days later, around November 2; in spring the one-in-ten date for 28°F is April 21, 13 days before the 32°F one. The freeze-free season lasts 189 days in a typical year, longer than at 62% of the 158 Illinois stations; it reaches 209 days one year in ten and falls short of 167 one year in ten. On average 118 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 27, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 2 and March 7.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 14 | Apr 18 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 4 | May 8 | May 14 |
| 32°F | Apr 2 | Apr 6 | Apr 10 | Apr 13 | Apr 16 | Apr 20 | Apr 23 | Apr 28 | May 4 |
| 28°F | Mar 19 | Mar 26 | Mar 31 | Apr 2 | Apr 5 | Apr 7 | Apr 11 | Apr 15 | Apr 21 |
| 24°F | Mar 8 | Mar 13 | Mar 17 | Mar 21 | Mar 26 | Mar 29 | Apr 1 | Apr 5 | Apr 10 |
| 20°F | Feb 28 | Mar 4 | Mar 8 | Mar 11 | Mar 15 | Mar 18 | Mar 21 | Mar 26 | Mar 31 |
| 16°F | Feb 17 | Feb 25 | Feb 28 | Mar 4 | Mar 7 | Mar 10 | Mar 14 | Mar 17 | Mar 23 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 28 | Oct 4 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 25 |
| 32°F | Oct 9 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 31 | Nov 3 |
| 28°F | Oct 21 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 11 | Nov 16 |
| 24°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 28 |
| 20°F | Nov 8 | Nov 12 | Nov 16 | Nov 19 | Nov 23 | Nov 26 | Nov 30 | Dec 3 | Dec 8 |
| 16°F | Nov 14 | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 5 | Dec 9 | Dec 13 | Dec 18 |
Freeze probabilities 1991–2020 at Peoria Gtr Peoria Airport, 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 61554 →Compare Pekin with another place →
Frost risk through the year in Pekin
In Pekin, the spring curve drops under 10% on May 4 and the fall curve passes 10% on October 9, 158 days later; that gap is longer than at 51% of the 158 Illinois stations with frost dates. The spring risk falls from 90% to 10% over 32 days (April 2 to May 4) and the fall risk climbs from 10% to 90% over 25 days (October 9 to November 3): the last frost moves more from year to year than the first. At Congerville 2NW, IL, 21 miles east, the same gap runs from May 7 to October 3, 9 days shorter.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Apr 2 | over 90% | 60% |
| Apr 9 | 73% | 35% |
| Apr 1650% date | 50% | 18% |
| Apr 23 | 30% | under 10% |
| Apr 30 | 17% | under 10% |
| May 7 | under 10% | under 10% |
Weather by month in Pekin
July is the warmest month at Peoria Gtr Peoria Airport, IL, averaging 86°F by day and 66°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 15% of years.
Warmth for growing adds up to 3,670 growing degree days a year (base 50°F), more than at 65% of the 158 Illinois stations. 36% of them (1,321) have built up by the end of June, and July adds the most, 815. Precipitation totals 37.6 inches a year, most in May (4.7") and least in February (2.0"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 34 | 18 | 2.1 | 100% | 28 | 1 |
| Feb | 39 | 21 | 2.0 | 100% | 24 | 5 |
| Mar | 51 | 32 | 2.7 | 100% | 17 | 45 |
| Apr | 64 | 42 | 4.0 | 91% | 4 | 163 |
| May | 74 | 53 | 4.7 | 15% | <1 | 423 |
| Jun | 83 | 62 | 3.7 | 0% | 0 | 684 |
| Jul | 86 | 66 | 3.5 | 0% | 0 | 815 |
| Aug | 85 | 64 | 3.3 | 0% | 0 | 759 |
| Sep | 78 | 56 | 3.5 | 4% | <1 | 523 |
| Oct | 65 | 44 | 3.2 | 82% | 3 | 209 |
| Nov | 51 | 33 | 2.7 | 100% | 15 | 40 |
| Dec | 39 | 23 | 2.2 | 100% | 25 | 4 |
Monthly normals 1991–2020 at Peoria Gtr Peoria Airport, IL (650 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, Congerville 2NW, IL, 21 miles east of Pekin, has a last frost 5 days later (April 21), a first frost 6 days earlier (October 17), a season 11 days shorter.
When it snows in Pekin, Illinois
The first measurable snow (0.1 inch or more) in Pekin usually arrives around December 1, and the last of the season around March 20. Those are the middle dates across the winters of 1991–2020 at Peoria Gtr Peoria Airport, IL, 7.4 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 27 days after the last snow.
Planting calendar for 61554
| When | What to do |
|---|---|
| February 5 – February 19 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 19 – March 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 19 – April 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 31 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 9 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 23 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 61554 is 7 miles from Peoria Gtr Peoria Airport, IL, which stands at 650 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 16 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 61554 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.