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Contents
- The climate of Grand Isle
- The best time to visit Grand Isle
- The worst time to visit Grand Isle
- Spring weather in Grand Isle
- Summer weather in Grand Isle
- Autumn weather in Grand Isle
- Winter weather in Grand Isle
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average snowfall days
- Average sea temperature
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
The scenic Grand Isle, Louisiana, with a view of the numerous houses and the extended piers onto the calm seawater
The climate of Grand Isle
Residing within the boundaries of Louisiana, USA, Grand Isle is classified under the Köppen climate system as a Cfa region, which denotes a humid subtropical climate with no dry season. The geographical positioning of Grand Isle, coupled with this particular climate classification, renders an overall climatic narrative of relatively high temperatures and varied humidity throughout the year.
When an analysis is cast onto the climate data of Grand Isle, it unveils a continual trend of high temperature values. The yearly average highs fluctuate from 61.7°F (16.5°C) in the coolest month to a sweltering 86.9°F (30.5°C) in the warmest months, coinciding with the cyclical pattern of seasonal variations. This contrast is echoed in the arena of average low temperatures, swinging between 53.1°F (11.7°C) and 81.3°F (27.4°C) during the course of the year.
Grand Isle's humidity, a salient feature of its climate, demonstrates a subtle range from 74% to 78% over the expanse of the year. Rainfall patterns also lend a unique aspect to Grand Isle's climate. Noteworthy patterns include the month of August, experiencing the maximum recorded rainfall averaging 4.72" (120mm) and February on the opposite end of the spectrum, evidenced by 0.87" (22mm) of rainfall, constituting the driest month annually.
When an analysis is cast onto the climate data of Grand Isle, it unveils a continual trend of high temperature values. The yearly average highs fluctuate from 61.7°F (16.5°C) in the coolest month to a sweltering 86.9°F (30.5°C) in the warmest months, coinciding with the cyclical pattern of seasonal variations. This contrast is echoed in the arena of average low temperatures, swinging between 53.1°F (11.7°C) and 81.3°F (27.4°C) during the course of the year.
Grand Isle's humidity, a salient feature of its climate, demonstrates a subtle range from 74% to 78% over the expanse of the year. Rainfall patterns also lend a unique aspect to Grand Isle's climate. Noteworthy patterns include the month of August, experiencing the maximum recorded rainfall averaging 4.72" (120mm) and February on the opposite end of the spectrum, evidenced by 0.87" (22mm) of rainfall, constituting the driest month annually.
The best time to visit Grand Isle
Discerning the ideal time to explore Grand Isle requires a thorough consideration of various weather parameters and their yearly variations. Balmy temperatures, coupled with ample daylight hours and simultaneous minimal rainfall, collectively fashion the ideal touristic ambiance. Hence April, bearing an average high temperature value around 74.3°F (23.5°C), 12.9 hours of daylight, and rainfall accounting to only 0.87" (22mm), is arguably the supreme time for visiting Grand Isle.
The worst time to visit Grand Isle
Contrastingly, the month of August sprawls as potentially the most challenging time to visit Grand Isle. This rationale pivots on several points, including the sweltering high temperatures averaging 86.9°F (30.5°C), coupled with palpably high humidity registering at 74%. Further aggravating this is the heaviest downpour of the year, reflecting in 4.72" (120mm) of rainfall, making it rather uncomfortable to explore the city.
Spring weather in Grand Isle
The progression of spring unfurls a spectral weather canvas from March to May in Grand Isle. March commences this journey on a relatively cool note, with highest temperature averages of 68.9°F (20.5°C), progressing to a warm 80.1°F (26.7°C) by May. Low temperatures follow a similar uptrend, escalating from 61.3°F (16.3°C) in March to 73.2°F (22.9°C) by the close of spring. An apparent increase in daylight hours occurs through this period, starting with 12 hours in March and culminating in a generous 13.6 hours in May.
Summer weather in Grand Isle
Summers in Grand Isle, spanning June to August, unveil an interplay of intensifying heat and heightened rainfall. High temperature averages surge from 85.5°F (29.7°C) in June to an arduous 86.9°F (30.5°C) in August while simultaneously witnessing a leap in rainfall from 2.13" (54mm) to 4.72" (120mm). Despite the testing weather conditions, the daylight hours remain at a steady high of 14 hours in June, slightly dipping to a still generous 13.2 hours in August.
Autumn weather in Grand Isle
Autumn drafts a transitional weather story from September through November. High temperatures moderate from 84.6°F (29.2°C) in September to a comparatively comfortable 69.8°F (21°C) in November while rainfall patterns recede from 2.17" (55mm) to a mere 1.38" (35mm). Daylight hours curtail considerably from 12.3 in September to a more limited 10.7 hours by the onset of November.
Winter weather in Grand Isle
The winter months of December through February roll out a decidedly cool narrative. High temperatures dwindle from 64.9°F (18.3°C) in December to the yearly low of 61.7°F (16.5°C) in January before minutely rebounding to 64.6°F (18.1°C) in February. Correspondingly, low temperatures fluctuate gently between 53.1°F (11.7°C) and 56.3°F (13.5°C) across these months. Coupled with limited daylight hours, a cloak of winter chill gently settles over Grand Isle during this period.
Weather in January
Grand Isle weather in January often paves the way five more months, with its lower temperatures, setting the tone for the first half of the year. Temperatures fluctuate from 53.1°F (11.7°C) to 61.7°F (16.5°C), showcasing the month's typical chill. Weather in January »
Weather in February
February in Grand Isle, Louisiana, continues the trend of its predecessor, with temperatures and rainfall showing a subtle increase. With the highest temperature recorded at 64.6°F (18.1°C), the month's comparative warmth starts to hint at the coming spring. Weather in February »
Weather in March
The turn of the season in March signals a significant shift in the Grand Isle weather pattern, with the temperature range extending up to 68.9°F (20.5°C). March brings with it an increase in daylight and sunshine hours consistent with the arrival of spring. Weather in March »
Weather in April
The weather in Grand Isle in April underlines the spring season's pinnacle with temperatures reaching up to 74.3°F (23.5°C). Consequently, the longer daylight hours and increased sunshine seem to be nature's way of celebrating spring in its full bloom in the city. Weather in April »
Weather in May
The weather in Grand Isle in May bears the hallmark of the ensuing summer season as the temperature ascends, with averages peaking at 80.1°F (26.7°C). Daylight hours stretched to 13.6 hours, accompanied by a proportional expansion in sunshine duration, confirming the impending arrival of summer. Weather in May »
Weather in June
June witnesses a gentle surge in the heat, with the temperature in Grand Isle scaling a high of 85.5°F (29.7°C), cozying up to the full-blown summer conditions. The confluence of longest daylight hours and the highest sunshine hours indicates the summer solstice's arrival. Weather in June »
Weather in July
July in Grand Isle is a summer month in the truest sense, with the highest temperature of the year at 86.9°F (30.5°C) and the most rainfall at 3.62" (92mm) over 19.8 days. Water activities can be enjoyed under the constant 14 hours of daylight, with the sea warming up to the year's highest temperature. Weather in July »
Weather in August
The specter of summer prevails in the Grand Isle weather in August, with temperatures matching the July peak at 86.9°F (30.5°C). However, an increase in rainfall to 4.72" (120mm) spread over 20.7 days prominently marks the month's weather. Weather in August »
Weather in September
Grand Isle weather in September initiates a shift towards more pleasant conditions, with the highest temperature at 84.6°F (29.2°C) commencing the slow descent into autumn. September begins witnessing shorter days and falling humidity levels, although the sea remains adequately warm for water activities. Weather in September »
Weather in October
October brings significant reprieve from the summer heat, dropping the temperature to a high of 78.3°F (25.7°C), a clear departure from September. In alignment with the season, the duration of daylight dips further, signaling the advance of autumn. Weather in October »
Weather in November
The weather in Grand Isle in November mirrors the larger weather trends of Louisiana in late autumn. The sun takes a backseat with temperatures cooling down to a high of 69.8°F (21°C), bolstered by comparably less humidity. Rainfall further cuts down, making days drier and cooler, more synonymous with the rest of Louisiana's weather pattern. Weather in November »
Weather in December
In December, the winter season's influence unmistakably enters Grand Isle’s weather, with the temperature tailing down to an annual low of 53.1°F (11.7°C). The city's cloud cover increases to a maximum 42%, concurring with the winter theme, reducing the influence of direct sunlight. Weather in December »
Updated: Jun 4, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What month is the coldest in Grand Isle?
The coldest period is January, when temperatures fluctuate between an average high of 61.7°F (16.5°C) and a low of 53.1°F (11.7°C).
How many days does it rain?
In Grand Isle, during the entire year, the rain falls for 151.9 days and collects up to 22.01" (559mm) of precipitation.
When does it snow?
The only month with snowfall is January.
When does it snow the most?
January has the most snowfall days of the year. Snow falls for 0.1 days.
How many days does it snow?
Throughout the year, there are 0.1 snowfall days.
What is the month with the coldest ocean?
January is the month with the coldest seawater, with an average ocean temperature of 61.3°F (16.3°C).
When is the lowest UV index?
The months with the lowest UV index are January and December, with an average maximum UV index of 4.
What are the most humid months?
The months with the highest humidity are February and December, with an average relative humidity of 78%.
What is the driest month?
February and April are months with the least rain when the rain falls for 9.7 days and typically aggregates up to 0.87" (22mm) of rain.
When it does not snow?
February through December are months without snowfall.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.
What are the months with the highest UV index?
The months with the highest UV index in Grand Isle are May through September, with an average maximum UV index of 7.
When are the longest days?
With an average of 14h and 0min of daylight, June has the longest days of the year.
What month has the most sunshine?
With an average of 11h of sunshine, June has the most sunshine of the year.
What is the hottest time of year?
Grand Isle witnesses its highest temperatures in July and August, reaching an average of 86.9°F (30.5°C).
What is the wettest month?
August is the month with the most rainfall. Rain falls for 20.7 days and accumulates 4.72" (120mm) of precipitation.
What month is the ocean warmest?
August is the month with the warmest seawater in Grand Isle, with an average ocean temperature of 87.4°F (30.8°C).
What is the least humid month?
October is the least humid month, with an average relative humidity of 71%.
What is the month with the shortest days in Grand Isle?
With an average of 10h and 18min of daylight, December has the shortest days of the year.
What is the month with the least sunshine?
With an average of 5.4h of sunshine, December has the least sunshine of the year in Grand Isle.
Average temperature
Grand Isle, LA
The warmest months (with the highest average high temperature) are July and August (86.9°F).
The month with the lowest average high temperature is January (61.7°F).
The month with the highest average low temperature is August (81.3°F).
The coldest month (with the lowest average low temperature) is January (53.1°F).
Average pressure
Grand Isle, LA
- Average pressure in January:
30.15"Hg - Average pressure in February:
30.1"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
30"Hg - Average pressure in May:
29.99"Hg - Average pressure in June:
29.97"Hg
- Average pressure in July:
30.01"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
29.96"Hg - Average pressure in October:
30.01"Hg - Average pressure in November:
30.11"Hg - Average pressure in December:
30.11"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is September (29.96"Hg).
Average wind speed
Grand Isle, LA
- Average wind speed in January:
12.4mph - Average wind speed in February:
11.9mph - Average wind speed in March:
11.6mph - Average wind speed in April:
12.1mph - Average wind speed in May:
10.1mph - Average wind speed in June:
8.8mph
- Average wind speed in July:
8mph - Average wind speed in August:
8.1mph - Average wind speed in September:
8.8mph - Average wind speed in October:
11mph - Average wind speed in November:
11.8mph - Average wind speed in December:
12.2mph
The windiest month (with the highest average wind speed) is January (12.4mph).
The calmest month (with the lowest average wind speed) is July (8mph).
Average humidity
Grand Isle, LA
The months with the highest relative humidity are February and December (78%).
The month with the lowest relative humidity is October (71%).
Average rainfall
Grand Isle, LA
- Average rainfall in January:
1.06" - Average rainfall in February:
0.87" - Average rainfall in March:
0.98" - Average rainfall in April:
0.87" - Average rainfall in May:
1.22" - Average rainfall in June:
2.13"
- Average rainfall in July:
3.62" - Average rainfall in August:
4.72" - Average rainfall in September:
2.17" - Average rainfall in October:
1.34" - Average rainfall in November:
1.38" - Average rainfall in December:
1.65"
The wettest month (with the highest rainfall) is August (4.72").
The driest months (with the least rainfall) are February and April (0.87").
Average rainfall days
Grand Isle, LA
- Average rainfall days in January:
10.3 days - Average rainfall days in February:
9.7 days - Average rainfall days in March:
10.4 days - Average rainfall days in April:
8.8 days - Average rainfall days in May:
10 days - Average rainfall days in June:
15.4 days
- Average rainfall days in July:
19.8 days - Average rainfall days in August:
20.7 days - Average rainfall days in September:
17.3 days - Average rainfall days in October:
10.1 days - Average rainfall days in November:
7.5 days - Average rainfall days in December:
11.9 days
The month with the highest number of rainy days is August (20.7 days).
The month with the least rainy days is November (7.5 days).
Average snowfall days
Grand Isle, LA
- Average snowfall days in January:
0.1 days - Average snowfall days in February:
0 days - Average snowfall days in March:
0 days - Average snowfall days in April:
0 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0 days - Average snowfall days in November:
0 days - Average snowfall days in December:
0 days
The month with the highest number of snowfall days is January (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October, November and December (0 days).
Average sea temperature
Grand Isle, LA
The best month for swimming (with the highest average sea temperature) is August (87.5°F).
The coldest month (with the lowest average sea temperature) is January (61.4°F).
Average daylight / Average sunshine
Grand Isle, LA
- Average daylight in January:
10h and 3min - Average daylight in February:
11h and 1min - Average daylight in March:
12h and 0min - Average daylight in April:
12h and 5min - Average daylight in May:
13h and 4min - Average daylight in June:
14h and 0min
- Average daylight in July:
13h and 5min - Average daylight in August:
13h and 1min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 3min - Average daylight in November:
10h and 4min - Average daylight in December:
10h and 2min
The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).
- Average sunshine in January:
6h and 0min - Average sunshine in February:
5h and 4min - Average sunshine in March:
8h and 2min - Average sunshine in April:
10h and 2min - Average sunshine in May:
10h and 5min - Average sunshine in June:
11h and 0min
- Average sunshine in July:
10h and 4min - Average sunshine in August:
10h and 5min - Average sunshine in September:
10h and 1min - Average sunshine in October:
7h and 3min - Average sunshine in November:
6h and 2min - Average sunshine in December:
5h and 2min
The month with the most sunshine is June (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 24min).
Average sunshine days
Grand Isle, LA
- Average sunshine days in January:
18.4 days - Average sunshine days in February:
16.8 days - Average sunshine days in March:
18.5 days - Average sunshine days in April:
18.6 days - Average sunshine days in May:
17.4 days - Average sunshine days in June:
11.4 days
- Average sunshine days in July:
8.3 days - Average sunshine days in August:
6.5 days - Average sunshine days in September:
8.6 days - Average sunshine days in October:
17.7 days - Average sunshine days in November:
19.5 days - Average sunshine days in December:
16.3 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is August (6.5 days).
Average UV index
Grand Isle, LA
The months with the highest UV index are May, June, July, August and September (UV index 7).
The months with the lowest UV index are January and December (UV index 4).
Average cloud cover
Grand Isle, LA
The month with the most cloud cover is December (Cloud cover 42).
The month with the least cloud cover is May (Cloud cover 23).
Average visibility
Grand Isle, LA
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Grand Isle, Louisiana, USA
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