Photo: Otebig · CC BY-SA 3.0Less rain and snow falls on Bly than on 94% of U.S. towns: 14 inches a year
Expect July afternoons of about 86°. The seasons are far apart: from a winter night to a summer afternoon the average spans 67°. Central heating does most of its work from October to April, in months below 50° on average.
A year in Bly at a glance
Each month’s typical high and low, and what it brings.
What stands out about Bly’s climate
Compared with towns across the U.S., with Bly’s place in Oregon beside it.
What a year in Bly feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 114 frost-free days a year
In half of years the last 32° night comes by May 31 and the first by September 21. Frost and day counts come from Gerber Dam, OR, 14 miles away.
The 2023 USDA map puts Bly’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −6°. 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 14 inches of rain a year
December is the wettest month and August the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Bly
98% 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 Gerber Dam, OR.
Living with Bly’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
114 frost-free days in zone 6a. The last frost comes by May 31 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 21.
1.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Bly from natural hazards, river flooding is the largest share (43%); heat waves, cold waves, winter storms and ice storms together are 5%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Bly and similar climates
TownRatings has no climate map of the towns around Bly 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 Bly averaged 1.7° warmer than the 1900s. The biggest change is in January (+3.6°).
A bigger shift than in 69% 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 Bly compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Bly’s place among Oregon’s.
Bly weather by month
Highs, lows and precipitation from NOAA’s grid at Bly’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 42° | 21° | 1.7" | 25° – 38° |
| February | 45° | 22° | 1.5" | 27° – 41° |
| March | 51° | 26° | 1.7" | 33° – 45° |
| April | 58° | 29° | 1.3" | 39° – 49° |
| May | 67° | 35° | 1.5" | 45° – 59° |
| June | 76° | 40° | 0.8" | 53° – 66° |
| July | 86° | 46° | 0.3" | 56° – 71° |
| August | 85° | 44° | 0.2" | 60° – 68° |
| September | 77° | 37° | 0.5" | 53° – 62° |
| October | 64° | 29° | 1.0" | 42° – 53° |
| November | 49° | 25° | 1.5" | 27° – 42° |
| December | 40° | 19° | 2.1" | 24° – 34° |
| Year | 62° | 31° | 14.1" |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 27° to 42°. September is the most reliable, staying within 9°.
Where Bly’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 Bly’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Gerber Dam, OR, 14 miles from the town’s center, 500 ft higher; no station nearby passes every check; this is the nearest one in the same valley, flagged above.
- 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 Bly’s climate
What is the weather like in Bly?
A typical July afternoon reaches 86°, a January night drops to 21°. Colder January nights than 56% of U.S. towns; hotter July afternoons than 58% of U.S. towns.
How cold does it get in Bly in winter?
December nights average 19°. About 191 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 24°.
How hot does it get in Bly?
July, with a typical high of 86° and a low of 46°. About 16 days a year reach 90° (Gerber Dam, OR).
When is the first and last frost in Bly?
In half of years the last spring frost (32°) comes by May 31 and the first fall frost by September 21, about 114 frost-free days, at Gerber Dam, OR.
What growing zone is Bly in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −6°.
What is the best time of year to visit Bly?
No month meets the simple rule we use (highs of 62–84° and lows of 40° or more). The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Bly getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 69% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Bly.
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.