USDA Hardiness Zone 5b
Frost Dates for 60021 — Fox River Grove, Illinois
NOAA 1991–2020 normals from Barrington 3SW, IL (875 ft), 6 miles southeast.
Updated
In Fox River Grove, the last spring frost (32°F) is around April 25 in half of years and has passed by May 12 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 177 days (NOAA, Barrington 3SW, IL).
- Last spring frost
- April 25
- First fall frost
- October 19
- Growing season
- 177 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
- November 23
- Last snow
- April 2
- Winters with snow
- 100%
- Snow per year
- 38.5"
median, 1991–2020
median, 1991–2020
25 of 25 observed
NOAA normal
Frost risk by date in Fox River Grove
Half of springs at Barrington 3SW, IL see their last 32°F night by April 25; only one in ten is past it by April 10, and one in ten still has one after May 12. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 5 20%, and after May 12 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 79% 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 November 1 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 30, 12 days before the 32°F one. The freeze-free season lasts 177 days in a typical year, shorter than at 72% of the 158 Illinois stations; it reaches 196 days one year in ten and falls short of 152 one year in ten. On average 137 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 May 6, and return around October 11. Severe cold of 16°F or below comes every winter, usually between November 29 and March 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 22 | Apr 27 | Apr 30 | May 3 | May 6 | May 9 | May 15 | May 19 | May 25 |
| 32°F | Apr 10 | Apr 15 | Apr 18 | Apr 21 | Apr 25 | Apr 28 | May 1 | May 5 | May 12 |
| 28°F | Mar 31 | Apr 4 | Apr 7 | Apr 9 | Apr 12 | Apr 16 | Apr 18 | Apr 23 | Apr 30 |
| 24°F | Mar 18 | Mar 23 | Mar 27 | Mar 31 | Apr 2 | Apr 4 | Apr 6 | Apr 10 | Apr 16 |
| 20°F | Mar 7 | Mar 12 | Mar 16 | Mar 19 | Mar 23 | Mar 25 | Mar 29 | Mar 31 | Apr 4 |
| 16°F | Feb 28 | Mar 4 | Mar 8 | Mar 11 | Mar 14 | Mar 17 | Mar 20 | Mar 24 | Mar 28 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 5 | Oct 8 | Oct 11 | Oct 13 | Oct 15 | Oct 18 | Oct 23 |
| 32°F | Oct 5 | Oct 11 | Oct 14 | Oct 17 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Nov 1 |
| 28°F | Oct 15 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 7 | Nov 12 |
| 24°F | Oct 27 | Nov 1 | Nov 2 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 24 |
| 20°F | Nov 4 | Nov 8 | Nov 12 | Nov 16 | Nov 19 | Nov 23 | Nov 26 | Nov 30 | Dec 4 |
| 16°F | Nov 12 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 1 | Dec 4 | Dec 8 | Dec 15 |
Freeze probabilities 1991–2020 at Barrington 3SW, 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 60021 →Compare Fox River Grove with another place →
Weather by month in Fox River Grove
July is the warmest month at Barrington 3SW, IL, averaging 81°F by day and 63°F at night; January is the coldest at 29°F and 13°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 31% of years.
Warmth for growing adds up to 2,764 growing degree days a year (base 50°F), fewer than at 95% of the 158 Illinois stations. 33% of them (921) have built up by the end of June, and July adds the most, 680. Precipitation totals 40.7 inches a year, most in May (5.2") and least in February (1.9"); May to September bring 54% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 29 | 13 | 2.1 | 100% | 29 | 0 |
| Feb | 33 | 16 | 1.9 | 100% | 27 | 1 |
| Mar | 45 | 27 | 2.4 | 100% | 22 | 17 |
| Apr | 58 | 37 | 4.0 | 99% | 8 | 84 |
| May | 69 | 48 | 5.2 | 31% | <1 | 284 |
| Jun | 78 | 58 | 4.6 | 1% | 0 | 535 |
| Jul | 81 | 63 | 4.0 | 0% | 0 | 680 |
| Aug | 79 | 61 | 4.6 | 0% | 0 | 626 |
| Sep | 72 | 54 | 3.7 | 5% | <1 | 395 |
| Oct | 60 | 42 | 3.4 | 89% | 5 | 123 |
| Nov | 46 | 30 | 2.6 | 100% | 18 | 18 |
| Dec | 34 | 20 | 2.2 | 100% | 28 | 1 |
Monthly normals 1991–2020 at Barrington 3SW, IL (875 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, Mc Henry -Wg Stratton L&D, IL, 8 miles north of Fox River Grove, has a last frost 6 days later (May 1), a first frost 8 days earlier (October 11), a season 15 days shorter.
When it snows in Fox River Grove, Illinois
The first measurable snow (0.1 inch or more) in Fox River Grove usually arrives around November 23, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Barrington 3SW, IL, 6.1 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 23 days after the last snow.
Planting calendar for 60021
| When | What to do |
|---|---|
| February 14 – February 28 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 28 – March 14 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 28 – April 11 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 25 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 60021 is 6 miles from Barrington 3SW, IL, which stands at 875 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 60010 (Barrington). The 2023 USDA Plant Hardiness Zone Map lists ZIP 60021 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.