Gorby Opera Theater · Photo: publichall · CC BY-SA 3.0Glenns Ferry reaches 100° on about 28 days a year, more than 97% of U.S. towns
On a normal January night the air cools to about 24°. Precipitation is light here, less than falls on almost every U.S. town. January has warmed most since 1901–2000, part of a 1.3° rise. Warm coats and heating bills mark the months from November to March, when means dip under 50°.
A year in Glenns Ferry at a glance
Each month’s typical high and low, and what it brings.
What stands out about Glenns Ferry’s climate
Compared with towns across the U.S., with Glenns Ferry’s place in Idaho beside it.
What a year in Glenns Ferry feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 154 frost-free days a year
In half of years the last 32° night comes by May 1 and the first by October 3. Frost and day counts come from NOAA’s station at Glenns Ferry, ID, 1.0 miles from the town’s center, at about the same height.
The 2023 USDA map puts Glenns Ferry’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 1°. 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 8 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 Glenns Ferry
81% of the work is heating. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Glenns Ferry, ID.
Living with Glenns Ferry’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
154 frost-free days in zone 7a. The last frost comes by May 1 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 3.
Months with highs of 62–84° and lows of 40° or more: May and September. 1.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Glenns Ferry from natural hazards, avalanches are the largest share (38%); heat waves, cold waves, winter storms and ice storms together are 3%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Glenns Ferry and similar climates
TownRatings has no climate map of the towns around Glenns Ferry 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 Glenns Ferry averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.2°).
A smaller shift than in 53% 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 Glenns Ferry compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Glenns Ferry’s place among Idaho’s.
Glenns Ferry weather by month
Highs, lows and precipitation from NOAA’s grid at Glenns Ferry’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 41° | 24° | 1.3" | 23° – 38° |
| February | 48° | 27° | 0.7" | 29° – 45° |
| March | 58° | 32° | 0.9" | 40° – 50° |
| April | 66° | 37° | 0.7" | 45° – 57° |
| May | 76° | 45° | 0.8" | 54° – 67° |
| June | 86° | 52° | 0.5" | 64° – 76° |
| July | 96° | 59° | 0.2" | 67° – 83° |
| August | 94° | 56° | 0.1" | 69° – 78° |
| September | 83° | 47° | 0.3" | 61° – 70° |
| October | 68° | 36° | 0.7" | 46° – 59° |
| November | 52° | 29° | 0.9" | 32° – 47° |
| December | 40° | 23° | 1.3" | 26° – 38° |
| Year | 67° | 39° | 8.3" |
How much a month can swing
A normal is an average. July swings the most: from 1991 to 2020 its average ranged from 67° to 83°. September is the most reliable, staying within 8°.
Where Glenns Ferry’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 Glenns Ferry’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Glenns Ferry, ID, 1.0 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 Glenns Ferry’s climate
What is the weather like in Glenns Ferry?
A typical July afternoon reaches 96°, a January night drops to 24°. Milder January nights than 60% of U.S. towns; hotter July afternoons than 97% of U.S. towns.
How cold does it get in Glenns Ferry in winter?
December nights average 23°. About 144 nights a year reach 32° or below and 2 reach 0° or below. In the coldest December of the last 30 years the month averaged 26°.
How hot does it get in Glenns Ferry?
July, with a typical high of 96° and a low of 59°. About 82 days a year reach 90° and 28 reach 100° (Glenns Ferry, ID).
When is the first and last frost in Glenns Ferry?
In half of years the last spring frost (32°) comes by May 1 and the first fall frost by October 3, about 154 frost-free days, at Glenns Ferry, ID.
What growing zone is Glenns Ferry in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 1°.
What is the best time of year to visit Glenns Ferry?
By one simple rule (highs of 62–84° and lows of 40° or more), May and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Glenns Ferry getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Glenns Ferry.
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.