This weather has a price Keeping the median Petroleum County home comfortable runs roughly $489 a year in heating and cooling alone. See where it lands in the monthly bill

30-year climate normals

Petroleum County Climate and Weather Averages

Hottest month: July

85.7°

average daily high. The coldest month is January, averaging a low of 6.3°F.

Petroleum County gets 14.6" of precipitation a year and 33.1" of snow, and 48% of it falls in May, Jun, Jul.

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	Snow
January	32.6°	6.3°	0.57"	7.1"
February	36.0°	10.0°	0.40"	5.1"
March	46.8°	19.4°	0.62"	4.8"
April	56.8°	29.2°	1.25"	2.7"
May	66.4°	39.2°	2.90"	0.5"
June	75.3°	48.7°	2.58"	0.0"
July	85.7°	53.8°	1.56"	0.0"
August	85.2°	51.8°	1.40"	0.0"
September	73.7°	41.5°	1.16"	0.0"
October	59.1°	29.5°	1.16"	1.8"
November	45.4°	17.8°	0.51"	4.3"
December	35.2°	8.9°	0.49"	6.8"

Rainfall by month

Petroleum County has a distinct wet season. 48% of the year's precipitation arrives in May, Jun, Jul.

January 0.57"

February 0.40"

March 0.62"

April 1.25"

May 2.90"

June 2.58"

July 1.56"

August 1.40"

September 1.16"

October 1.16"

November 0.51"

December 0.49"

Annual total 14.6"

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 411

Heating degree days How much heating the climate demands 8,058

Approximate annual cooling cost At 15.14¢/kWh, Montana average $62

Approximate annual electric heating cost Lower where heating is gas rather than electric $427

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 Petroleum County, where electricity is one line of eight.

Common questions

What is the weather like in Petroleum County?

Petroleum County averages a high of 85.7°F in July and a low of 6.3°F in January. Annual precipitation is 14.6 inches, including 33.1 inches of snow.

When is the rainy season in Petroleum County?

The wettest stretch is May, Jun, Jul, which accounts for 48% of the year's precipitation. That is a pronounced wet season rather than rain spread evenly through the year.

How hot does it get in Petroleum County?

The average daily high in July, the hottest month, is 85.7°F. That drives 411 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Petroleum County?

Yes. Petroleum County averages 33.1 inches of snow a year.

Sources

Temperature, precipitation and snowfall normals: NOAA National Centers for Environmental Information, 1991 to 2020 Monthly Climate Normals, station VALENTINE, MT US (USC00248498), 18.7 miles from the county centroid.
Heating and cooling degree days: NOAA, same station and period.
Annual figures on this page are the sum of that station's twelve monthly normals. NOAA also publishes a separately-computed annual normal, which can differ from the monthly sum by a few percent; we use the monthly series because the month-by-month breakdown above has to come from it.
Electricity price: US Energy Information Administration, Electric Power Monthly Table 5.6.A, Montana residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.