30-year climate normals

St. Tammany Parish Climate and Weather Averages

Hottest month — August

91.2°

average daily high. The coldest month is January, averaging a low of 40.7°F.

St. Tammany Parish gets 61.88" of precipitation a year, and 33% of it falls in Jun, Jul, Aug.

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	62.0°	40.7°	5.57"
February	65.9°	44.4°	4.14"
March	71.8°	50.0°	4.94"
April	77.9°	56.1°	5.21"
May	84.9°	63.8°	5.46"
June	89.7°	70.9°	6.11"
July	91.1°	73.1°	7.25"
August	91.2°	72.9°	6.96"
September	88.0°	68.5°	4.14"
October	80.5°	57.4°	3.72"
November	71.0°	46.7°	3.89"
December	64.3°	42.8°	4.49"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 33% falling in the wettest three months (Jun, Jul, Aug).

January 5.57"

February 4.14"

March 4.94"

April 5.21"

May 5.46"

June 6.11"

July 7.25"

August 6.96"

September 4.14"

October 3.72"

November 3.89"

December 4.49"

Annual total 61.88"

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 2,634

Heating degree days How much heating the climate demands 1,612

Approximate annual cooling cost At 14.15¢/kWh, Louisiana average $373

Approximate annual electric heating cost Lower where heating is gas rather than electric $80

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 St. Tammany Parish, where electricity is one line of eight.

Common questions

What is the weather like in St. Tammany Parish?

St. Tammany Parish averages a high of 91.2°F in August and a low of 40.7°F in January. Annual precipitation is 61.88 inches, with essentially no snow.

When is the rainy season in St. Tammany Parish?

The wettest stretch is Jun, Jul, Aug, which accounts for 33% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in St. Tammany Parish?

The average daily high in August, the hottest month, is 91.2°F. That drives 2,634 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in St. Tammany Parish?

Effectively no. Measurable snowfall is rare in St. Tammany Parish.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station SLIDELL AP, LA US (USW00053865), 9 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, Louisiana residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.