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Will it freeze in Portland 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 43°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 43°F Above 36°F · Partly Cloudy
- Fri, Nov 6 36°F Frost possible · Partly Cloudy
- Sat, Nov 7 32°F Freeze · Areas Of Fog
- Sun, Nov 8 33°F Frost possible · Mostly Clear
- Mon, Nov 9 36°F Frost possible · Mostly Clear
- Tue, Nov 10 37°F Above 36°F · Mostly Clear
- Wed, Nov 11 39°F Above 36°F · Mostly Clear
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 Portland
The median first fall hard-freeze date (28°F) is November 11, from NOAA’s 1991–2020 Climate Normals at Portland Sewage Plt. 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 2 · Apr 16 · May 2 | Oct 12 · Oct 23 · Nov 3 | 188 days |
| 32°F freeze | Mar 21 · Apr 5 · Apr 19 | Oct 21 · Nov 1 · Nov 14 | 210 days |
| 28°F hard freeze | Mar 5 · Mar 26 · Apr 9 | Oct 31 · Nov 11 · Nov 29 | 231 days |
Average high temperature by month
1991–2020 normals at Portland Sewage Plt
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 Portland, TN come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Portland Sewage Plt (station USC00407359, elevation 794 ft), 0.7 mi from Portland. 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 Portland
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Franklin, KY | 8.7 mi | Apr 5 | Nov 1 |
| White House, TN | 12 mi | Apr 7 | Oct 30 |
| Gallatin, TN | 16 mi | Apr 16 | Oct 23 |
| Millersville, TN | 17 mi | Apr 7 | Oct 30 |
| Greenbrier, TN | 19 mi | Apr 9 | Oct 28 |
| Springfield, TN | 21 mi | Apr 9 | Oct 28 |
| Hendersonville, TN | 21 mi | Apr 11 | Oct 29 |
| Goodlettsville, TN | 21 mi | Apr 11 | Oct 29 |
| Hartsville, TN | 25 mi | Apr 12 | Oct 26 |
| Russellville, KY | 26 mi | Apr 9 | Oct 28 |
Frequently asked questions
When is the last frost in Portland?
On average, the last spring frost (32°F) in Portland is around April 5. In about 1 year in 10 it comes after April 19, and in 9 years in 10 it comes after March 21.
When is the first frost in Portland?
The first fall frost (32°F) usually arrives around November 1. There’s a 10% chance of a freeze by October 21 and a 90% chance by November 14.
Can it frost in Portland 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 April 16.
What growing zone is Portland?
Portland is in USDA Plant Hardiness Zone 7b (average annual extreme minimum temperature 5 to 10°F), based on the 2023 USDA map for ZIP code 37148. See growing zones in Tennessee.
More: all Tennessee frost dates · Tennessee growing zones · frost vs. freeze