Glenns Ferry, Idaho climate: Normal weather by month, frost dates and records
Glenns Ferry's normal year runs from 25°F December nights to 99°F July afternoons, with 10.6 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.6°C, December lows of −4°C, July highs of 37°C, 269 mm of precipitation a year.
- NOAA stationGlenns Ferry
- Station IDUSC00103631
- Location42.94°N 115.32°W
- Elevation2,466 ft (752 m)
- Population1,288
On October 22, the normal high in Glenns Ferry is 68°F and the normal low 34°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Glenns Ferry.
- Jan 44° 25°
- Feb 50° 27°
- Mar 60° 32°
- Apr 68° 38°
- May 79° 46°
- Jun 88° 53°
- Jul 99° 59°
- Aug 97° 56°
- Sep 86° 46°
- Oct 71° 36°
- Nov 55° 29°
- Dec 44° 25°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Glenns Ferry each month?
July is the warmest month, with normal highs of 99°F; December the coldest, with normal lows of 25°F. The most precipitation falls in December (1.56 in), the least in July (0.23 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 44°F | 25°F | 34.3°F | 1.50 | – | <1 | 26 | 9 h 20 min |
| February | 50°F | 27°F | 38.4°F | 0.82 | – | <1 | 23 | 10 h 30 min |
| March | 60°F | 32°F | 46.2°F | 1.01 | – | <1 | 20 | 11 h 50 min |
| April | 68°F | 38°F | 52.7°F | 0.89 | – | <1 | 11 | 13 h 20 min |
| May | 79°F | 46°F | 62.0°F | 1.07 | – | 4 | 2 | 14 h 40 min |
| June | 88°F | 53°F | 70.3°F | 0.71 | – | 12 | <1 | 15 h 20 min |
| July | 99°F | 59°F | 78.8°F | 0.23 | – | 27 | <1 | 15 h |
| August | 97°F | 56°F | 76.4°F | 0.28 | – | 26 | <1 | 14 h |
| September | 86°F | 46°F | 66.2°F | 0.44 | – | 11 | 2 | 12 h 30 min |
| October | 71°F | 36°F | 53.7°F | 0.98 | – | 1 | 12 | 11 h 10 min |
| November | 55°F | 29°F | 42.0°F | 1.11 | – | <1 | 23 | 9 h 50 min |
| December | 44°F | 25°F | 34.2°F | 1.56 | – | <1 | 26 | 9 h |
| Year (annual) | 70°F | 39°F | 54.6°F | 10.60 | – | 82 | 144 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 7°C | −4°C | 1.3°C | 38 mm |
| February | 10°C | −3°C | 3.6°C | 21 mm |
| March | 16°C | 0°C | 7.9°C | 26 mm |
| April | 20°C | 3°C | 11.5°C | 23 mm |
| May | 26°C | 8°C | 16.7°C | 27 mm |
| June | 31°C | 11°C | 21.3°C | 18 mm |
| July | 37°C | 15°C | 26.0°C | 6 mm |
| August | 36°C | 13°C | 24.7°C | 7 mm |
| September | 30°C | 8°C | 19.0°C | 11 mm |
| October | 22°C | 2°C | 12.1°C | 25 mm |
| November | 13°C | −2°C | 5.6°C | 28 mm |
| December | 7°C | −4°C | 1.2°C | 40 mm |
NOAA publishes no 1991-2020 snowfall normal for this station, and no record within 25 miles keeps one, so snow is left out here rather than estimated.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00103631; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Glenns Ferry?
Normal highs sit between 65°F and 85°F in April, May and October.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00103631.
When is the last frost in Glenns Ferry?
In Glenns Ferry, the last spring frost (32°F) comes after May 1 in half of years and after May 16 in one year in ten; the first autumn frost comes before October 3 in half of years and before September 16 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 11 year in 10 after May 16; 9 in 10 after April 14
- First autumn frost, half of years before
- October 31 year in 10 before September 16; 9 in 10 before October 19
NOAA puts the median frost-free season at 154 days, and the season without a hard freeze (28°F) at 184 days.
A hard freeze (28°F) comes after April 15 in half of springs and before October 16 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Glenns Ferry in zone 7a in ZIP code 83623, the nearest ZIP area.
Frost dates for every NOAA station in Idaho · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00103631; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Glenns Ferry?
In a normal year in Glenns Ferry, 82 days a year reach 90°F (28 of them 100°F or more) and 144 nights fall to 32°F or colder.
- Days at 90°F or more
- 82a normal year
- Days at 100°F or more
- 28a normal year
- Nights at 32°F or colder
- 144a normal year
- Days that stay below freezing
- 8high of 32°F or less
The highest temperature in this station's record (since 1905) is 115°F, on July 16, 1925; the lowest is −28°F, on December 25, 1924.
The wettest calendar year on that record is 1970, with 18.83 in; the snowiest season is 1971–72, with 35.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00103631; records: ACIS (NOAA Regional Climate Centers), station USC00103631. Records use complete months only; a month missing more than three days is left out.
How sunny is Glenns Ferry?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Glenns Ferry, 4.6 kWh per square metre a day. July is the sunniest month (90%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 66% | 1.9 |
| February | 68% | 2.7 |
| March | 72% | 4.1 |
| April | 76% | 5.5 |
| May | 79% | 6.7 |
| June | 86% | 7.6 |
| July | 90% | 7.6 |
| August | 89% | 6.6 |
| September | 88% | 5.3 |
| October | 82% | 3.6 |
| November | 73% | 2.2 |
| December | 62% | 1.5 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Glenns Ferry need?
A normal year in Glenns Ferry brings 4,934 heating degree days, 8% fewer than the median U.S. place (5,373), and 1,173 cooling degree days, 29% more than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,542 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 952 | 0 |
| February | 745 | 0 |
| March | 583 | 0 |
| April | 375 | 6 |
| May | 155 | 62 |
| June | 38 | 196 |
| July | 2 | 431 |
| August | 6 | 361 |
| September | 74 | 110 |
| October | 359 | 7 |
| November | 692 | 0 |
| December | 955 | 0 |
| Year (annual) | 4,934 | 1,173 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00103631. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Glenns Ferry been warmer than normal lately?
2024 averaged 55.4°F, 0.8°F above the 1991-2020 normal of 54.6°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 56.1°F | +1.5°F | 8.97 |
| 2022 | 53.0°F | −1.6°F | 8.13 |
| 2023 | 55.3°F | +0.7°F | 7.28 |
| 2024 | 55.4°F | +0.8°F | 9.08 |
Source: observed years: ACIS, station USC00103631. A year counts only with all twelve months complete.
How does Glenns Ferry's climate compare?
Glenns Ferry is warmer than 83 of the other 84 places with their own NOAA record in Idaho, and wetter than 21. Across the 7,247 U.S. stations with normals, its annual mean of 54.6°F is warmer than 59%.
In the Köppen classification computed from these normals, Glenns Ferry is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Glenns Ferry share this climate record?
Hammett has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Hammett, ID258 people · 7 mi W
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Glenns Ferry's climate
What is the coldest month in Glenns Ferry?
December, with a normal high of 44°F and a normal low of 25°F. The warmest is July (99°F by day, 59°F at night).
What is the rainiest month in Glenns Ferry?
December, with 1.56 in of precipitation in a normal year; the driest is July with 0.23 in.
What plant hardiness zone is Glenns Ferry in?
The USDA's 2023 map puts Glenns Ferry in zone 7a in ZIP code 83623, the nearest ZIP area.
How late can frost come in Glenns Ferry?
In half of years the last 32°F night comes after May 1; in one year in ten it comes after May 16. Waiting until May 16 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Idaho climateThe statewide normals and every place in the state
- Hagerman, ID22 miles from this station, 50.6°F a year
- Mountain Home, ID24 miles from this station, 52.3°F a year
- Bruneau, ID25 miles from this station, 55.2°F a year
- Hill City (1 mi W), ID28 miles from this station, 42.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made