Grand Isle, LA climate
Grand Isle has warm winters and warm summers, with plenty of rain. A typical July afternoon reaches 89°, a January night drops to 49°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Grand Isle feels like
Winter
Spring
Summer
Fall
Grand Isle weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 62° | 49° | 5.1" | 0 | 8 | 0 | 48° – 62° |
| February | 65° | 52° | 3.5" | 0 | 7 | 0 | 49° – 68° |
| March | 70° | 57° | 4.1" | 0 | 6 | 0 | 57° – 71° |
| April | 76° | 64° | 4.5" | 0 | 5 | 0 | 64° – 74° |
| May | 83° | 71° | 4.6" | 0 | 5 | 0 | 73° – 80° |
| June | 88° | 77° | 6.5" | 0 | 9 | 0 | 80° – 85° |
| July | 89° | 78° | 7.6" | 0 | 11 | 0 | 82° – 87° |
| August | 89° | 78° | 7.6" | 0 | 9 | 0 | 81° – 87° |
| September | 86° | 75° | 6.5" | 0 | 9 | 0 | 78° – 84° |
| October | 79° | 67° | 4.0" | 0 | 6 | 0 | 70° – 78° |
| November | 70° | 57° | 3.7" | 0 | 5 | 0 | 58° – 69° |
| December | 65° | 51° | 4.3" | 0 | 7 | 0 | 52° – 66° |
| Year | 77° | 65° | 62.2" | 0.0" | 84 | 0 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Grand Isle
Grand Isle gets 62 inches of rain and melted snow a year. July is the wettest month and February the driest. Rain or snow falls on about 84 days a year.
About 311 frost-free days a year
In half of years the last 32° night comes by February 8 and the first one by December 19. That leaves about 311 frost-free days for gardens, longer than 95% of U.S. towns.
Heating and cooling a home in Grand Isle
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Grand Isle, 31% of that work is heating and 69% is cooling, so air conditioning is the bigger bill.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Grand Isle compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Grand Isle averaged 0.9° warmer than the 1900s. The biggest change is in February (+1.5°). The shift is smaller than in 75% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Grand Isle’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 49° to 68°. June is the most reliable, staying within 5°.
Common questions about Grand Isle’s climate
What is the coldest month in Grand Isle?
January, with a typical high of 62° and a low of 49°.
What is the hottest month in Grand Isle?
July, with a typical high of 89° and a low of 78°. About 49 days a year reach 90°.
How much snow does Grand Isle get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Grand Isle?
In half of years the first 32° night comes by December 19, and the last spring frost by February 8.
What is the rainiest month in Grand Isle?
July, with 7.6 inches of rain and melted snow. The year totals 62 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Grand Isle itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Grand Isle, LA (3 mi, snow) and Galliano, LA (24 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.