Photo: Karen Apricot · CC BY-SA 2.0Grand Isle sits near the top of U.S. towns for precipitation, with 62 inches a year
Midsummer highs settle at about 89°. July is the wettest month, February the driest. Its January nights stay gentler than in 96% of U.S. towns. Plan time outside from October to May, when highs sit at 62–83°.
A year in Grand Isle at a glance
Each month’s typical high and low, and what it brings.
What stands out about Grand Isle’s climate
Compared with towns across the U.S., with Grand Isle’s place in Louisiana beside it.
What a year in Grand Isle feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 311 frost-free days a year
In half of years the last 32° night comes by February 8 and the first by December 19. Frost and day counts come from NOAA’s station at Galliano, LA, 24 miles from the town’s center, at about the same height.
The 2023 USDA map puts Grand Isle’s center in zone 10a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 33°. 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
July is the wettest month and February the driest. Rain falls on about 84 days a year. Snow is rare: about 0.0" in a normal year at Grand Isle, LA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Grand Isle
31% of the work is heating, so air conditioning is the bigger bill. No month averages under 55°.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Galliano, LA.
Living with Grand Isle’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
311 frost-free days in zone 10a. The last frost comes by Feb 8 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 19.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, May, October, November and December. 9.4 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Grand Isle from natural hazards, coastal flooding is the largest share (68%). Normals are averages; the hazards page covers the extremes.
Natural hazards →Grand Isle and similar climates
TownRatings has no climate map of the towns around Grand Isle yet.
Climates most like Grand Isle’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 |
|---|---|---|---|---|
| Grand Isle, LA | 49° | 89° | 62" | 0.0" |
| Gulf Breeze, FL | 44° | 90° | 62" | 0.0" |
| Gulf Shores, AL | 44° | 90° | 62" | 0.0" |
| Port Arthur, TX | 44° | 91° | 61" | 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.
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°).
A smaller shift than in 82% of 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 Grand Isle compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Grand Isle’s place among Louisiana’s.
Grand Isle weather by month
Highs, lows and precipitation from NOAA’s grid at Grand Isle’s center; snow, wet days and snow on the ground from Grand Isle, LA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 62° | 49° | 5.1" | 0.0" | 8 | 0 | 48° – 62° |
| February | 65° | 52° | 3.5" | 0.0" | 7 | 0 | 49° – 68° |
| March | 70° | 57° | 4.1" | 0.0" | 6 | 0 | 57° – 71° |
| April | 76° | 64° | 4.5" | 0.0" | 5 | 0 | 64° – 74° |
| May | 83° | 71° | 4.6" | 0.0" | 5 | 0 | 73° – 80° |
| June | 88° | 77° | 6.5" | 0.0" | 9 | 0 | 80° – 85° |
| July | 89° | 78° | 7.6" | 0.0" | 11 | 0 | 82° – 87° |
| August | 89° | 78° | 7.6" | 0.0" | 9 | 0 | 81° – 87° |
| September | 86° | 75° | 6.5" | 0.0" | 9 | 0 | 78° – 84° |
| October | 79° | 67° | 4.0" | 0.0" | 6 | 0 | 70° – 78° |
| November | 70° | 57° | 3.7" | 0.0" | 5 | 0 | 58° – 69° |
| December | 65° | 51° | 4.3" | 0.0" | 7 | 0 | 52° – 66° |
| Year | 77° | 65° | 62.2" | 0.0" | 84 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 49° to 68°. June is the most reliable, staying within 5°.
Where Grand Isle’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 Grand Isle’s center.
- Snow: Grand Isle, LA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Galliano, LA, 24 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 Grand Isle’s climate
What is the weather like in Grand Isle?
A typical July afternoon reaches 89°, a January night drops to 49°, and snow is almost unheard of. Milder January nights than 96% of U.S. towns; hotter July afternoons than 74% of U.S. towns.
How cold does it get in Grand Isle in winter?
January nights average 49°. About 9 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 48°.
How much snow does Grand Isle get?
About 0.0 inches in a normal winter at Grand Isle, LA, so most winters see none.
How hot does it get in Grand Isle?
July, with a typical high of 89° and a low of 78°. About 49 days a year reach 90° (Galliano, LA).
When is the first and last frost in Grand Isle?
In half of years the last spring frost (32°) comes by February 8 and the first fall frost by December 19, about 311 frost-free days, at Galliano, LA.
What growing zone is Grand Isle in?
Zone 10a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 33°.
What is the best time of year to visit Grand Isle?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Grand Isle getting warmer?
Yes: 1991–2020 averaged 0.9° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 82% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Grand Isle.
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.