Hardly any U.S. towns collect more precipitation than Mermentau: 62 inches a year
Nights in January average 42°. June is the wettest month, March the driest. Its January nights stay gentler than in 91% of U.S. towns. For walks and days out, the stretch from February to April and October to December brings highs of 64–81°.
A year in Mermentau at a glance
Each month’s typical high and low, and what it brings.
What stands out about Mermentau’s climate
Compared with towns across the U.S., with Mermentau’s place in Louisiana beside it.
What a year in Mermentau feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 292 frost-free days a year
In half of years the last 32° night comes by February 19 and the first by December 4. Frost and day counts come from NOAA’s station at Jennings, LA, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Mermentau’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 24°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 62 inches of rain a year
June is the wettest month and March the driest. Rain falls on about 124 days a year. Snow is rare: about 0.1" in a normal year at Jennings, LA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Mermentau
38% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55°: December and January.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Jennings, LA.
Living with Mermentau’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
292 frost-free days in zone 9a. The last frost comes by Feb 19 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Dec 4.
Months with highs of 62–84° and lows of 40° or more: February, March, April, October, November and December.
Parks & trails →Of the yearly building losses FEMA expects in Mermentau from natural hazards, river flooding is the largest share (43%); heat waves, cold waves, winter storms and ice storms together are 8%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Mermentau and similar climates
TownRatings has no climate map of the towns around Mermentau yet.
Climates most like Mermentau’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Mermentau, LA | 42° | 92° | 62" | 0.1" |
| Milton, FL | 41° | 91° | 63" | 0.1" |
| Foley, AL | 42° | 91° | 63" | 0.1" |
| Picayune, MS | 40° | 91° | 65" | 0.0" |
| Magalia, CA | 38° | 92° | 61" | 0.1" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
About as warm as it used to be
The last 30 years in Mermentau averaged 0.2° warmer than the 1900s. The biggest change is in February (+1.0°).
A smaller shift than in all but 27 U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Mermentau compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Mermentau’s place among Louisiana’s.
Mermentau weather by month
Highs, lows and precipitation from NOAA’s grid at Mermentau’s center; snow, wet days and snow on the ground from Jennings, LA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 62° | 42° | 6.1" | 0.0" | 12 | 0 | 45° – 59° |
| February | 66° | 46° | 4.2" | 0.0" | 10 | 0 | 47° – 64° |
| March | 72° | 52° | 3.6" | 0.0" | 9 | 0 | 56° – 69° |
| April | 78° | 58° | 4.8" | 0.0" | 8 | 0 | 64° – 73° |
| May | 85° | 66° | 5.4" | 0.0" | 8 | 0 | 73° – 79° |
| June | 90° | 72° | 6.3" | 0.0" | 12 | 0 | 79° – 84° |
| July | 92° | 74° | 5.8" | 0.0" | 14 | 0 | 81° – 85° |
| August | 92° | 74° | 6.2" | 0.0" | 13 | 0 | 79° – 86° |
| September | 89° | 69° | 5.2" | 0.0" | 10 | 0 | 76° – 82° |
| October | 81° | 59° | 4.6" | 0.0" | 8 | 0 | 66° – 76° |
| November | 71° | 50° | 4.8" | 0.0" | 9 | 0 | 55° – 65° |
| December | 64° | 44° | 4.9" | 0.1" | 11 | 0 | 47° – 61° |
| Year | 78° | 59° | 62.0" | 0.1" | 124 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 47° to 64°. July is the most reliable, staying within 4°.
Where Mermentau’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Mermentau’s center.
- Snow: Jennings, LA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Jennings, LA, 5 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Mermentau’s climate
What is the weather like in Mermentau?
A typical July afternoon reaches 92°, a January night drops to 42°, and snow is almost unheard of. Milder January nights than 91% of U.S. towns; hotter July afternoons than 86% of U.S. towns.
How cold does it get in Mermentau in winter?
January nights average 42°. About 15 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 45°.
How much snow does Mermentau get?
About 0.1 inches in a normal winter at Jennings, LA, so most winters see none.
How hot does it get in Mermentau?
July, with a typical high of 92° and a low of 74°. About 73 days a year reach 90° (Jennings, LA).
When is the first and last frost in Mermentau?
In half of years the last spring frost (32°) comes by February 19 and the first fall frost by December 4, about 292 frost-free days, at Jennings, LA.
What growing zone is Mermentau in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 24°.
What is the best time of year to visit Mermentau?
By one simple rule (highs of 62–84° and lows of 40° or more), February, March, April, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Mermentau getting warmer?
Yes: 1991–2020 averaged 0.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than all but 27 U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Mermentau.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.