30-year climate normals

Jerome County Climate and Weather Averages

Hottest month — July

89.6°

average daily high. The coldest month is January, averaging a low of 22.5°F.

Jerome County gets 9.9" of precipitation a year, and 36% of it falls in Mar, Apr, May.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	35.7°	22.5°	1.21"
February	41.4°	25.2°	0.72"
March	52.6°	31.7°	1.10"
April	59.9°	36.3°	1.06"
May	69.5°	44.2°	1.44"
June	79.3°	51.3°	0.62"
July	89.6°	58.7°	0.11"
August	87.6°	56.5°	0.27"
September	77.5°	48.9°	0.33"
October	62.8°	38.7°	0.77"
November	47.7°	29.1°	0.96"
December	36.0°	22.5°	1.31"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 36% falling in the wettest three months (Mar, Apr, May).

January 1.21"

February 0.72"

March 1.10"

April 1.06"

May 1.44"

June 0.62"

July 0.11"

August 0.27"

September 0.33"

October 0.77"

November 0.96"

December 1.31"

Annual total 9.9"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 714

Heating degree days How much heating the climate demands 6,073

Approximate annual cooling cost At 12.35¢/kWh, Idaho average $88

Approximate annual electric heating cost Lower where heating is gas rather than electric $263

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Jerome County, where electricity is one line of eight.

Common questions

What is the weather like in Jerome County?

Jerome County averages a high of 89.6°F in July and a low of 22.5°F in January. Annual precipitation is 9.9 inches, with essentially no snow.

When is the rainy season in Jerome County?

The wettest stretch is Mar, Apr, May, which accounts for 36% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Jerome County?

The average daily high in July, the hottest month, is 89.6°F. That drives 714 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Jerome County?

Effectively no. Measurable snowfall is rare in Jerome County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station JEROME CO AP, ID US (USW00004110), 10.2 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, Idaho residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.