Photo: Kingofthedead · CC BY-SA 4.0Three Rivers’ winters are milder but snowier than most of the U.S.
A typical July afternoon reaches 83°, a January night drops to 22°, and about 74 inches of snow falls in a normal winter.
A year in Three Rivers at a glance
Each month’s typical high and low, and what it brings.
What stands out about Three Rivers’ climate
Compared with towns across the U.S., with Three Rivers’ place in Oregon beside it.
What a year in Three Rivers 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 231 nights a year fall to 32° or below, and 5 to 0° or below. Frost and day counts come from NOAA’s station at Sunriver, OR, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Three Rivers’ center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −7°. 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 74 inches of snow a winter
Snow, measured at Wickiup Dam, OR, falls mostly in December. Precipitation (rain plus melted snow) adds up to 21 inches a year; December is the wettest month and August the driest. Rain or snow falls on about 102 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Three Rivers
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 Sunriver, OR.
Living with Three Rivers’ 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 42 days.
Months with highs of 62–84° and lows of 40° or more: July and August. 4.8 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Three Rivers from natural hazards, river flooding is the largest share (86%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Three Rivers and similar climates
TownRatings has no climate map of the towns around Three Rivers yet.
Climates most like Three Rivers’, 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 |
|---|---|---|---|---|
| Three Rivers, OR | 22° | 83° | 21" | 74" |
| Whitefish, MT | 17° | 82° | 18" | 63" |
| Big Bear City, CA | 27° | 81° | 18" | 59" |
| Moscow, ID | 25° | 84° | 25" | 51" |
| Flagstaff, AZ | 16° | 84° | 18" | 90" |
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 Three Rivers averaged 1.0° warmer than the 1900s. The biggest change is in January (+3.5°).
A smaller shift than in 76% 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 Three Rivers compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Three Rivers’ place among Oregon’s.
Three Rivers weather by month
Highs, lows and precipitation from NOAA’s grid at Three Rivers’ center; snow, wet days and snow on the ground from Wickiup Dam, OR. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 41° | 22° | 2.9" | 17.9" | 13 | 27 | 24° – 38° |
| February | 43° | 22° | 1.9" | 14.9" | 11 | 22 | 25° – 41° |
| March | 49° | 25° | 2.3" | 8.4" | 12 | 16 | 32° – 44° |
| April | 55° | 28° | 1.5" | 2.0" | 10 | 3 | 36° – 48° |
| May | 64° | 35° | 1.7" | 0.3" | 9 | 0 | 43° – 56° |
| June | 72° | 39° | 0.9" | 0.0" | 6 | 0 | 51° – 64° |
| July | 83° | 45° | 0.5" | 0.0" | 3 | 0 | 54° – 68° |
| August | 82° | 44° | 0.5" | 0.0" | 3 | 0 | 58° – 68° |
| September | 74° | 38° | 0.7" | 0.0" | 4 | 0 | 52° – 61° |
| October | 60° | 31° | 1.6" | 0.8" | 8 | 1 | 41° – 52° |
| November | 46° | 26° | 2.6" | 8.9" | 12 | 8 | 29° – 41° |
| December | 39° | 21° | 3.6" | 20.7" | 14 | 21 | 24° – 33° |
| Year | 59° | 31° | 20.6" | 73.9" | 102 | 98 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 25° to 41°. September is the most reliable, staying within 9°.
Where Three Rivers’ 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 Three Rivers’ center.
- Snow: Wickiup Dam, OR.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sunriver, OR, 5 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 Three Rivers’ climate
What is the weather like in Three Rivers?
A typical July afternoon reaches 83°, a January night drops to 22°, and about 74 inches of snow falls in a normal winter. Milder January nights than 52% of U.S. towns; cooler July afternoons than 74% of U.S. towns.
How cold does it get in Three Rivers in winter?
December nights average 21°. About 231 nights a year reach 32° or below and 5 reach 0° or below. In the coldest December of the last 30 years the month averaged 24°.
How much snow does Three Rivers get?
About 74 inches in a normal winter at Wickiup Dam, OR, most of it in December, with snow on the ground about 98 days a year.
How hot does it get in Three Rivers?
July, with a typical high of 83° and a low of 45°. About 19 days a year reach 90° (Sunriver, OR).
When is the first and last frost in Three Rivers?
There is no reliable frost-free season: at Sunriver, OR, every month has nights at 32° or below, about 231 a year. In half of years the longest stretch without a freeze is about 42 days.
What growing zone is Three Rivers in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −7°.
What is the best time of year to visit Three Rivers?
By one simple rule (highs of 62–84° and lows of 40° or more), July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Three Rivers getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 76% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Three Rivers.
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.