St. Mary Parish Climate
St. Mary Parish, Louisiana
Avg Annual Temp
69.6°F
Annual Precip
61.9"
Annual Snowfall
0.0"
Extreme Heat Days
50.7
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About St. Mary Parish Weather
One of America’s warmest parishes
St. Mary Parish averages 69.6°F annually, placing it nearly 15 degrees above the national median temperature. This coastal climate is defined by mild winters and a persistent, heavy maritime influence.
Surpassing the state average
At 69.6°F, the parish is nearly three degrees warmer than the Louisiana state average of 67.0°F. It ranks as one of the warmest regions in the state due to its southern, coastal position.
Matching the Terrebonne profile
St. Mary shares an identical annual average temperature of 69.6°F with neighboring Terrebonne Parish. Both areas benefit from coastal breezes that limit extreme heat days to 51 per year, fewer than inland parishes.
Warm winters and tempered heat
July averages 82.9°F, but the proximity to the Gulf keeps extreme heat days to a manageable 51. Winters are very mild with a 55.5°F average, and snow is virtually non-existent.
Designed for coastal living
Homeowners should focus on salt-air resistant materials and robust cooling systems for the 82.4°F summers. With 61.9 inches of rain, consistent rain gear is more important than any winter clothing.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.