St. Mary Parish Climate
St. Mary Parish, Louisiana
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
69.6°F
Annual Precip
61.9"
Annual Snowfall
0.0"
Extreme Heat Days
51
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
9b
Minimum winter temperature range for plant survival
7,339
Excellent for heat-loving crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: St. Mary Parish
Climate Verdict
St. Mary Parish has a warm, averaging 69.6°F year-round, very wet conditions receiving 61.9 inches of precipitation annually, occasional hot days — 50.699999999999996 per year above 90°F, virtually no measurable snowfall. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are mild, with January temperatures averaging 53.7°F. summers are hot, with July averaging 82.9°F. The climate is remarkably stable year-round, with only a 29°F difference between January and July. January is typically the coldest month and August the warmest.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for St. Mary Parish. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
St. Mary Parish closely matches the Louisiana statewide average temperature of 67.0°F, the county experiences 32.96634615384611 fewer extreme heat days than the state average.
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 sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.