Jerome, Idaho climate: Normal weather by month, frost dates and records
Jerome's normal year runs from 23°F January nights to 90°F July afternoons, with 9.9 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.1°C, January lows of −5°C, July highs of 32°C, 251 mm of precipitation a year.
- NOAA stationJerome County Airport
- Station IDUSW00004110
- Location42.73°N 114.46°W
- Elevation4,048 ft (1,234 m)
- Population13,481
On October 22, the normal high in Jerome is 60°F and the normal low 37°F, and the chance of measurable rain or snow is 18%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Jerome.
- Jan 36° 23°
- Feb 41° 25°
- Mar 53° 32°
- Apr 60° 36°
- May 70° 44°
- Jun 79° 51°
- Jul 90° 59°
- Aug 88° 57°
- Sep 78° 49°
- Oct 63° 39°
- Nov 48° 29°
- Dec 36° 23°
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 Jerome each month?
July is the warmest month, with normal highs of 90°F; January the coldest, with normal lows of 23°F. The most precipitation falls in May (1.44 in), the least in July (0.11 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 36°F | 23°F | 29.1°F | 1.21 | 9 | <1 | 29 | 9 h 20 min |
| February | 41°F | 25°F | 33.3°F | 0.72 | 8 | <1 | 24 | 10 h 30 min |
| March | 53°F | 32°F | 42.1°F | 1.10 | 9 | <1 | 19 | 11 h 50 min |
| April | 60°F | 36°F | 48.1°F | 1.06 | 8 | <1 | 11 | 13 h 20 min |
| May | 70°F | 44°F | 56.8°F | 1.44 | 8 | <1 | 2 | 14 h 40 min |
| June | 79°F | 51°F | 65.3°F | 0.62 | 5 | 4 | <1 | 15 h 20 min |
| July | 90°F | 59°F | 74.1°F | 0.11 | 2 | 17 | <1 | 15 h |
| August | 88°F | 57°F | 72.0°F | 0.27 | 2 | 12 | <1 | 14 h |
| September | 78°F | 49°F | 63.2°F | 0.33 | 4 | 2 | 1 | 12 h 30 min |
| October | 63°F | 39°F | 50.8°F | 0.77 | 5 | <1 | 7 | 11 h 10 min |
| November | 48°F | 29°F | 38.4°F | 0.96 | 8 | <1 | 21 | 9 h 50 min |
| December | 36°F | 23°F | 29.3°F | 1.31 | 11 | <1 | 28 | 9 h |
| Year (annual) | 62°F | 39°F | 50.2°F | 9.90 | 78 | 35 | 142 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 2°C | −5°C | −1.6°C | 31 mm |
| February | 5°C | −4°C | 0.7°C | 18 mm |
| March | 11°C | 0°C | 5.6°C | 28 mm |
| April | 16°C | 2°C | 8.9°C | 27 mm |
| May | 21°C | 7°C | 13.8°C | 37 mm |
| June | 26°C | 11°C | 18.5°C | 16 mm |
| July | 32°C | 15°C | 23.4°C | 3 mm |
| August | 31°C | 14°C | 22.2°C | 7 mm |
| September | 25°C | 9°C | 17.3°C | 8 mm |
| October | 17°C | 4°C | 10.4°C | 20 mm |
| November | 9°C | −2°C | 3.6°C | 24 mm |
| December | 2°C | −5°C | −1.5°C | 33 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Twin Falls (6 mi E) (14 miles away), gets 24 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00004110; 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 Jerome?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (4).
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 USW00004110.
When is the last frost in Jerome?
In Jerome, 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 14 in half of years and before September 29 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 17
- First autumn frost, half of years before
- October 141 year in 10 before September 29; 9 in 10 before October 28
NOAA puts the median frost-free season at 165 days, and the season without a hard freeze (28°F) at 192 days.
A hard freeze (28°F) comes after April 15 in half of springs and before October 26 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Jerome in zone 6b in ZIP code 83338, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Jerome's NOAA station is in zone 7a: the coldest night of a typical year reaches 0°F (18 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Idaho · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00004110; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 Jerome?
In a normal year in Jerome, 35 days a year reach 90°F (1 of them 100°F or more), 142 nights fall to 32°F or colder and 78 days bring measurable precipitation.
- Days at 90°F or more
- 35a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 142a normal year
- Days that stay below freezing
- 32high of 32°F or less
- Days with 0.01 inch of precipitation
- 78a normal year
The highest temperature in Jerome's official record (kept by the National Weather Service since 1915) is 110°F, on June 19, 1940; the lowest is −25°F, on January 21, 1937.
The wettest calendar year on that record is 1995, with 17.98 in; the snowiest season is 1948–49, with 53.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00004110; records: ACIS (NOAA Regional Climate Centers), NWS threaded record JERthr. Records use complete months only; a month missing more than three days is left out.
How sunny is Jerome?
Over a year 81% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Jerome, 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 | 69% | 1.9 |
| February | 69% | 2.8 |
| March | 72% | 4.0 |
| April | 76% | 5.5 |
| May | 80% | 6.7 |
| June | 86% | 7.6 |
| July | 90% | 7.6 |
| August | 89% | 6.6 |
| September | 87% | 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 Jerome need?
A normal year in Jerome brings 6,073 heating degree days, 13% more than the median U.S. place (5,373), and 714 cooling degree days, 21% fewer 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 2,738 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,113 | 0 |
| February | 888 | 0 |
| March | 709 | 0 |
| April | 508 | 1 |
| May | 273 | 20 |
| June | 89 | 98 |
| July | 6 | 290 |
| August | 13 | 232 |
| September | 124 | 70 |
| October | 446 | 4 |
| November | 798 | 0 |
| December | 1,108 | 0 |
| Year (annual) | 6,073 | 714 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00004110. 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 Jerome been warmer than normal lately?
2025 averaged 52.0°F, 1.8°F above the 1991-2020 normal of 50.2°F. 3 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 52.2°F | +2.0°F | 7.08 |
| 2022 | 48.7°F | −1.5°F | 6.68 |
| 2023 | 49.4°F | −0.8°F | 8.98 |
| 2024 | 51.2°F | +1.0°F | 7.97 |
| 2025 | 52.0°F | +1.8°F | 6.94 |
Source: observed years: ACIS, station USW00004110. A year counts only with all twelve months complete.
How does Jerome's climate compare?
Jerome is warmer than 67 of the other 84 places with their own NOAA record in Idaho, and wetter than 11. Across the 7,247 U.S. stations with normals, its annual mean of 50.2°F is warmer than 41%.
In the Köppen classification computed from these normals, Jerome 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.
What do Jerome's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Jerome. This page uses Jerome County Airport; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Jerome station USC00104670 | 3 mi W | 3,740 ft | 50.1°F | 22°F | 90°F | 10.4 | – | May 2 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Jerome's climate
What is the coldest month in Jerome?
January, with a normal high of 36°F and a normal low of 23°F. The warmest is July (90°F by day, 59°F at night).
Does it snow in Jerome?
Yes. NOAA publishes no 1991-2020 snowfall normal for Jerome's NOAA station; the nearest record that keeps one, Twin Falls (6 mi E) (14 miles away), records 24 inches of snow in a normal year.
What is the rainiest month in Jerome?
May, with 1.44 in of precipitation in a normal year; the driest is July with 0.11 in.
What plant hardiness zone is Jerome in?
The USDA's 2023 map puts Jerome in zone 6b in ZIP code 83338, the nearest ZIP area. By the same method at Jerome's NOAA station, the coldest night of a typical year reaches 0°F (18 years, 1991-2020): zone 7a.
How late can frost come in Jerome?
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
- Twin Falls-KMVT, ID10 miles from this station, 51.6°F a year
- Shoshone, ID15 miles from this station, 52.7°F a year
- Twin Falls, ID17 miles from this station, 49.1°F a year
- Buhl, ID17 miles from this station, 50.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made