Photo: Doug from Portland, USA · CC BY 2.0Dry weather: only 21 inches of rain and melted snow a year in Sumpter, less than in 89% of U.S. towns
The coldest hours of a January night bottom out at 17° on average. By July afternoons alone, it runs cooler than 83% of U.S. towns. Since 1901–2000, the year has warmed by 1.6°, most of all in January. Keep the boiler serviced for the months from October to May, which average under 50°.
A year in Sumpter at a glance
Each month’s typical high and low, and what it brings.
What stands out about Sumpter’s climate
Compared with towns across the U.S., with Sumpter’s place in Oregon beside it.
What a year in Sumpter feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
A freeze is possible in every month
About 245 nights a year fall to 32° or below, and 12 to 0° or below. Frost and day counts come from NOAA’s station at Austin 3 S, OR, 19 miles from the town’s center, 260 ft lower.
The 2023 USDA map puts Sumpter’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −9°. 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 21 inches of rain a year
December is the wettest month and July the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Sumpter
99% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Austin 3 S, OR.
Living with Sumpter’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 6a, and frost can come in any month. The longest frost-free stretch in half of years is about 74 days.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 4.2 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Sumpter from natural hazards, wildfire is the largest share (44%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Sumpter and similar climates
TownRatings has no climate map of the towns around Sumpter yet.
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 Sumpter averaged 1.6° warmer than the 1900s. The biggest change is in January (+3.8°).
A bigger shift than in 68% 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 Sumpter compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Sumpter’s place among Oregon’s.
Sumpter weather by month
Highs, lows and precipitation from NOAA’s grid at Sumpter’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 35° | 17° | 2.8" | 18° – 31° |
| February | 40° | 19° | 2.1" | 23° – 37° |
| March | 47° | 25° | 2.1" | 31° – 42° |
| April | 54° | 29° | 1.6" | 36° – 48° |
| May | 63° | 35° | 1.9" | 43° – 54° |
| June | 70° | 40° | 1.4" | 51° – 63° |
| July | 82° | 46° | 0.6" | 53° – 69° |
| August | 82° | 45° | 0.6" | 59° – 67° |
| September | 73° | 38° | 0.6" | 52° – 60° |
| October | 58° | 31° | 1.4" | 38° – 51° |
| November | 43° | 24° | 2.4" | 26° – 39° |
| December | 34° | 17° | 3.4" | 19° – 30° |
| Year | 57° | 30° | 20.9" |
How much a month can swing
A normal is an average. July swings the most: from 1991 to 2020 its average ranged from 53° to 69°. September is the most reliable, staying within 8°.
Where Sumpter’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 Sumpter’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Austin 3 S, OR, 19 miles from the town’s center, 260 ft lower; 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 Sumpter’s climate
What is the weather like in Sumpter?
A typical July afternoon reaches 82°, a January night drops to 17°. Colder January nights than 73% of U.S. towns; cooler July afternoons than 83% of U.S. towns.
How cold does it get in Sumpter in winter?
January nights average 17°. About 245 nights a year reach 32° or below and 12 reach 0° or below. In the coldest January of the last 30 years the month averaged 18°.
How hot does it get in Sumpter?
July, with a typical high of 82° and a low of 46°. About 21 days a year reach 90° (Austin 3 S, OR).
When is the first and last frost in Sumpter?
There is no reliable frost-free season: at Austin 3 S, OR, every month has nights at 32° or below, about 245 a year. In half of years the longest stretch without a freeze is about 74 days.
What growing zone is Sumpter in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −9°.
What is the best time of year to visit Sumpter?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Sumpter getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 68% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Sumpter.
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.