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Will it freeze in St. John in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Sat, Nov 7: 32°F (Sat, Nov 7, 6:00 PM CST to Sun, Nov 8, 6:00 AM CST).
Tonight: forecast low 40°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
3 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 40°F Above 36°F · Chance Rain Showers then Cloudy
- Fri, Nov 6 34°F Frost possible · Partly Cloudy
- Sat, Nov 7 32°F Freeze · Mostly Clear
- Sun, Nov 8 34°F Frost possible · Mostly Clear
- Mon, Nov 9 40°F Above 36°F · Mostly Clear
- Tue, Nov 10 38°F Above 36°F · Partly Cloudy
- Wed, Nov 11 39°F Above 36°F · Partly Cloudy
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in St. John
The median first fall hard-freeze date (28°F) is October 30, from NOAA’s 1991–2020 Climate Normals at Park Forest. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 20 · May 5 · May 24 | Sep 27 · Oct 10 · Oct 22 | 157 days |
| 32°F freeze | Apr 9 · Apr 23 · May 11 | Oct 6 · Oct 20 · Nov 1 | 179 days |
| 28°F hard freeze | Mar 30 · Apr 12 · Apr 27 | Oct 18 · Oct 30 · Nov 15 | 202 days |
Average high temperature by month
1991–2020 normals at Park Forest
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for St. John, IN come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Park Forest (station USC00116616, elevation 710 ft), 12 mi from St. John. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near St. John
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Schererville, IN | 3.1 mi | Apr 23 | Oct 20 |
| Dyer, IN | 4.3 mi | Apr 23 | Oct 20 |
| Cedar Lake, IN | 5.0 mi | Apr 29 | Oct 16 |
| Sauk Village, IL | 6.2 mi | Apr 23 | Oct 20 |
| Griffith, IN | 6.2 mi | Apr 23 | Oct 20 |
| Crown Point, IN | 6.8 mi | Apr 29 | Oct 16 |
| Lynwood, IL | 6.8 mi | Apr 23 | Oct 20 |
| Highland, IN | 7.5 mi | Apr 23 | Oct 20 |
| Munster, IN | 7.5 mi | Apr 23 | Oct 20 |
| Merrillville, IN | 8.1 mi | Apr 22 | Oct 25 |
Frequently asked questions
When is the last frost in St. John?
On average, the last spring frost (32°F) in St. John is around April 23. In about 1 year in 10 it comes after May 11, and in 9 years in 10 it comes after April 9.
When is the first frost in St. John?
The first fall frost (32°F) usually arrives around October 20. There’s a 10% chance of a freeze by October 6 and a 90% chance by November 1.
Can it frost in St. John after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after May 5.
What growing zone is St. John?
St. John is in USDA Plant Hardiness Zone 6a (average annual extreme minimum temperature −10 to −5°F), based on the 2023 USDA map for ZIP code 46373. See growing zones in Indiana.
More: all Indiana frost dates · Indiana growing zones · frost vs. freeze