Photo: Ichabod · CC BY-SA 3.0Portland gets more rain and snow than 90% of U.S. towns: 53 inches of precipitation a year
January mornings start at about 28°. From frosty January to warm July, readings climb 61°. Winters are mild: January nights here are milder than in 69% of U.S. towns. The frost-free window for a garden runs roughly April 5 to November 1.
A year in Portland at a glance
Each month’s typical high and low, and what it brings.
What stands out about Portland’s climate
Compared with towns across the U.S., with Portland’s place in Tennessee beside it.
What a year in Portland feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 210 frost-free days a year
In half of years the last 32° night comes by April 5 and the first by November 1. Frost and day counts come from NOAA’s station at Portland Sewage Plt, TN, 0.7 miles from the town’s center, at about the same height.
The 2023 USDA map puts Portland’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 5°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 2 inches of snow a winter
Snow, measured at Portland Sewage Plt, TN, falls mostly in February. Precipitation (rain plus melted snow) adds up to 53 inches a year; May is the wettest month and October the driest. Rain or snow falls on about 119 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Portland
72% of the work is heating. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Portland Sewage Plt, TN.
Living with Portland’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
210 frost-free days in zone 7b. The last frost comes by Apr 5 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 1.
Months with highs of 62–84° and lows of 40° or more: April, May, September and October. 3.6 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Portland from natural hazards, tornadoes are the largest share (25%); heat waves, cold waves, winter storms and ice storms together are 20%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Portland and similar climates
TownRatings has no climate map of the towns around Portland yet.
Climates most like Portland’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Portland, TN | 28° | 88° | 53" | 2.0" |
| Lenoir, NC | 28° | 88° | 50" | 4.1" |
| Canton, GA | 31° | 88° | 54" | 1.3" |
| Suffolk, VA | 30° | 89° | 50" | 4.1" |
| Sikeston, MO | 28° | 90° | 49" | 3.1" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Portland averaged 0.7° warmer than the 1900s. The biggest change is in February (+1.8°).
A smaller shift than in 93% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Portland compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Portland’s place among Tennessee’s.
Portland weather by month
Highs, lows and precipitation from NOAA’s grid at Portland’s center; snow, wet days and snow on the ground from Portland Sewage Plt, TN. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 45° | 28° | 4.1" | 0.2" | 11 | 0 | 28° – 45° |
| February | 51° | 31° | 4.3" | 1.5" | 10 | 1 | 29° – 49° |
| March | 59° | 38° | 4.8" | 0.3" | 12 | 0 | 42° – 60° |
| April | 70° | 46° | 4.9" | 0.0" | 11 | 0 | 51° – 62° |
| May | 78° | 56° | 5.6" | 0.0" | 11 | 0 | 61° – 73° |
| June | 85° | 63° | 4.5" | 0.0" | 10 | 0 | 70° – 79° |
| July | 88° | 68° | 4.6" | 0.0" | 10 | 0 | 74° – 82° |
| August | 88° | 66° | 3.7" | 0.0" | 8 | 0 | 72° – 84° |
| September | 82° | 58° | 3.8" | 0.0" | 8 | 0 | 66° – 76° |
| October | 71° | 47° | 3.7" | 0.0" | 8 | 0 | 55° – 65° |
| November | 59° | 37° | 3.7" | 0.0" | 9 | 0 | 41° – 53° |
| December | 49° | 31° | 4.9" | 0.0" | 11 | 0 | 28° – 51° |
| Year | 69° | 47° | 52.5" | 2.0" | 119 | 1 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 28° to 51°. July is the most reliable, staying within 8°.
Where Portland’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Portland’s center.
- Snow: Portland Sewage Plt, TN (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Portland Sewage Plt, TN, 0.7 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Portland’s climate
What is the weather like in Portland?
A typical July afternoon reaches 88°, a January night drops to 28°, and about 2 inches of snow falls in a normal winter. Milder January nights than 69% of U.S. towns; hotter July afternoons than 69% of U.S. towns.
How cold does it get in Portland in winter?
January nights average 28°. About 80 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 28°.
How much snow does Portland get?
About 2.0 inches in a normal winter at Portland Sewage Plt, TN, most of it in February, with snow on the ground about 1 days a year.
How hot does it get in Portland?
July, with a typical high of 88° and a low of 68°. About 38 days a year reach 90° (Portland Sewage Plt, TN).
When is the first and last frost in Portland?
In half of years the last spring frost (32°) comes by April 5 and the first fall frost by November 1, about 210 frost-free days, at Portland Sewage Plt, TN.
What growing zone is Portland in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 5°.
What is the best time of year to visit Portland?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Portland getting warmer?
Yes: 1991–2020 averaged 0.7° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 93% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Portland.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.