30-year climate normals

Collin County Climate and Weather Averages

Hottest month — August

95.5°

average daily high. The coldest month is January, averaging a low of 33.9°F.

Collin County gets 38.3" of precipitation a year, and 31% of it falls in Apr, May, Jun.

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	55.5°	33.9°	2.70"
February	59.7°	38.1°	2.57"
March	67.5°	45.5°	3.51"
April	74.7°	53.0°	3.58"
May	82.8°	62.4°	4.77"
June	90.7°	70.2°	3.58"
July	95.0°	73.8°	1.96"
August	95.5°	73.1°	1.73"
September	88.3°	65.5°	2.81"
October	77.9°	54.2°	4.41"
November	66.2°	43.7°	3.19"
December	57.1°	35.8°	3.49"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 31% falling in the wettest three months (Apr, May, Jun).

January 2.70"

February 2.57"

March 3.51"

April 3.58"

May 4.77"

June 3.58"

July 1.96"

August 1.73"

September 2.81"

October 4.41"

November 3.19"

December 3.49"

Annual total 38.3"

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 2,531

Heating degree days How much heating the climate demands 2,497

Approximate annual cooling cost At 16.44¢/kWh, Texas average $416

Approximate annual electric heating cost Lower where heating is gas rather than electric $144

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 Collin County, where electricity is one line of eight.

Common questions

What is the weather like in Collin County?

Collin County averages a high of 95.5°F in August and a low of 33.9°F in January. Annual precipitation is 38.3 inches, with essentially no snow.

When is the rainy season in Collin County?

The wettest stretch is Apr, May, Jun, which accounts for 31% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Collin County?

The average daily high in August, the hottest month, is 95.5°F. That drives 2,531 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Collin County?

Effectively no. Measurable snowfall is rare in Collin County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station MCKINNEY MUNI AP, TX US (USW00053914), 1.2 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, Texas residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.