Climate and monthly weather forecast
Sanibel, FL

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A large flock of the iconic royal tern birds on the white sandy shores on a typical beach in Sanibel, Florida
A large flock of the iconic royal tern birds on the white sandy shores on a typical beach in Sanibel, Florida

The climate of Sanibel

Sanibel, Florida, USA, lies under the Köppen climate classification of Aw, known as the tropical savanna climate. This location experiences significant seasonal changes in precipitation, while the temperatures remain relatively constant throughout the year.

Generally, Sanibel maintains high average temperatures between 69.8°F (21°C) and 88°F (31.1°C), which is typical of locations within the tropical savanna zone. The constant warmth is reflected in the sea temperatures, which range from 65.3°F (18.5°C) to 87.1°F (30.6°C). A noticeable difference in rainfall patterns manifests throughout the year. Dry periods are observed during winter, with rainfall averages from 1.06" (27mm) to 1.57" (40mm), while the summer months attract higher rainfall volumes, reaching up to 8.54" (217mm) in August.

Complementing the rainfall patterns is the relative humidity, which oscillates between 73% and 77% across different months, presenting slightly higher levels during the wetter seasons. Similarly, the number of rainfall days shows an increase during summer and a decrease during the dryer winter months. Sunshine hours also correspond to weather changes, with shorter sunshine durations coinciding with periods of higher rainfall. Wind speeds vary slightly throughout the year, ranging from 6.9mph (11.1km/h) to 10.1mph (16.3km/h).

Unexpected weather patterns appear around pressure levels across the year. The highest pressure reading of 30.11" (765mm) is observed in January, while the lowest of 29.95" (761mm) occurs in September.

The best time to visit Sanibel

A visit to Sanibel would be best timed for the spring between March and May. During this timeframe, the weather is comfortable, with temperatures fluctuating from 64°F (17.8°C) to 82.9°F (28.3°C), and relatively drier conditions with an average rainfall of 1.46" (37mm) in May. This period also provides longer daylight hours, increasing from 12 hours in March to 13.5 hours in May. Consequently, visitors can enjoy more outdoor activities during their stay.

The worst time to visit Sanibel

The least favorable time for a visit to Sanibel would be the peak summer period between June and August. This period records the highest rainfall averages, going up to 8.54" (217mm) in August. Combined with average high temperatures of 87.4°F (30.8°C) in July and 88°F (31.1°C) in August, and this could result in discomfort for visitors unaccustomed to tropical climates.

Spring weather in Sanibel

In the spring, the temperatures in Sanibel gradually increase from average lows of 64°F (17.8°C) in March to highs of 82.9°F (28.3°C) in May. The rainfall remains relatively low, with an average of 1.46" (37mm) in May. The days become longer, with up to 13.5 hours of daylight in May, providing ample time for enjoying outdoor activities.

Summer weather in Sanibel

Come summer, Sanibel sees a considerable increase in rainfall, recording the highest average of 8.54" (217mm) in August. The temperatures become less variegated during this time, generally around 86°F (30°C) to 88°F (31.1°C). Daylight hours are marginally longer, providing up to 13.8 hours of daylight in June. However, cloud cover increases during this period, which might slightly reduce the amount of sunshine received.

Autumn weather in Sanibel

As autumn sets in, the temperatures start to cool down and range from 74.3°F (23.5°C) to 82.9°F (28.3°C). The autumn period sees a decrease in rainfall from 6.18" (157mm) in September to 1.22" (31mm) in November. And the daylight hours start to reduce, with 10.9 hours of daylight by November.

Winter weather in Sanibel

In winter, Sanibel experiences cooler temperatures ranging from 59.5°F (15.3°C) to 73.9°F (23.3°C). The rainfall is at its lowest during these months, with an average inch count of 1.57" (40mm) in December. Despite the cooler conditions, the sea temperatures remain relatively warm, hovering around 65°F (18.3°C), providing a lovely contrast to the cooler air temperatures. The daylight hours decrease further, with around 10.5 hours of daylight in December.

Weather in January

Sanibel's weather towards the start of the year reveals a climate combining humidity, rainfall, and mild temperatures. Despite its placement in winter, Sanibel experiences a relatively warm January, with temperatures rarely dipping below the pleasant mark. Weather in January »

Weather in February

As Sanibel transitions from January to February, notable shifts in climatic elements occur. Despite February's marginally increased environmental pressures, the February climate remains welcoming with ample daylight and enjoyable sea temperatures. Weather in February »

Weather in March

Distinct seasonal shifts mark Sanibel's transition from February to March. In March, the city experiences warm weather, alongside an increase in daily sunshine hours. The island embraces March with a higher average temperature of 74.5°F (23.6°C), demonstrating the city's transition towards the warm season. Weather in March »

Weather in April

When it comes to April, Sanibel's weather takes on a markedly warmer character, sharply contrasting with the preceding months. April's climate has typical characteristics of increased heat, sunshine hours, while still maintaining fair sea temperatures. Weather in April »

Weather in May

May in Sanibel showcases a noticeable rise in temperature, reflecting the city's move deeper into its warm season. May features noticeable heat accompanied by an increase in rainfall, emphasizing the month's role as a transition period. Weather in May »

Weather in June

Come June, Sanibel's weather varies noticeably from that of May. June introduces appreciable adjustments in the city's climate, aligning more with summer norms of high heat and rainfall. The average daily temperature reaches around 86°F (30°C), testifying to the city's warm season. Weather in June »

Weather in July

July in Sanibel is characterized by sweltering weather, high rainfall, and excessively warm sea temperatures. The city experiences its maximum weather extremities in July, with hotter days and increasing amounts of rainfall. Noteworthy, July registers the highest average temperature with a reading of 88°F (31.1°C), ranking it as the hottest month of the year. Weather in July »

Weather in August

August's weather continues in the same vein as July’s, with high heat and substantial rainfall. Despite the formidable weather elements, Sanibel's August climate remains suited to outdoor activities, thanks to its significant daylight and sunshine hours. Weather in August »

Weather in September

Sanibel's weather shows a subtle shift as September comes around, bringing slightly cooler days and a decrease in rainfall. September signifies the gradual conclusion of the hot season, marking the beginning of the city's transition towards its cooler period. Weather in September »

Weather in October

October's weather in Sanibel shows a discernible divergence from September, characterized by moderating heat and diminishing rainfall. October's climate features milder temperatures, a reduction in rain frequencies, and lesser daylight hours. Weather in October »

Weather in November

November's weather in Sanibel shows a significant departure from October, denoted by cooler days and further decreased rainfall. November symbolizes the onset of the cooler season, featuring lower temperatures and a marked reduction in rainfall levels. Weather in November »

Weather in December

Coming to December, Sanibel's weather takes on its coolest avatar, with the lowest heat levels of the year. December's climate caps off the year with its shortest days, lowest temperatures, and relative lack of rainfall. Ranking as one of the coolest months, December sees the city's average daily temperature drop to an enjoyable 73.9°F (23.3°C). Weather in December »
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the coldest in Sanibel?

During the coldest month in Sanibel, January, temperatures average a high of 69.8°F (21°C) and a low of 59.5°F (15.3°C).

How many days does it rain in Sanibel?

Throughout the year, in Sanibel, Florida, there are 190.9 rainfall days, and 41.73" (1060mm) of precipitation is accumulated.

What month is the ocean coldest in Sanibel?

The month with the coldest seawater in Sanibel is January, with an average ocean temperature of 65.3°F (18.5°C).

When is the lowest UV index in Sanibel?

January and February, with an average maximum UV index of 5, are months with the lowest UV index.

What is the driest month in Sanibel?

February is the month with the least rainfall in Sanibel. Rain falls for 8.2 days and accumulates 1.06" (27mm) of precipitation.

What is the least humid month in Sanibel?

The months with the lowest humidity are March, May, July, August and October, with an average relative humidity of 73%.

When is Daylight Saving Time (DST) in Sanibel?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.

What month has the most sunshine in Sanibel?

With an average of 11h of sunshine, May has the most sunshine of the year in Sanibel.

When is the highest UV index in Sanibel?

The months with the highest UV index in Sanibel are May through September, with an average maximum UV index of 7.

When are the longest days in Sanibel?

The month with the longest days in Sanibel, Florida, is June, with an average of 13h and 48min of daylight.

What part of the year is the hottest in Sanibel?

August, noted for its average high-temperature of 88°F (31.1°C) and an average low-temperature of 81.1°F (27.3°C), is considered the warmest month in Sanibel, Florida.

What is the wettest month in Sanibel?

August is the month with the most rainfall. Rain falls for 27.3 days and accumulates 8.54" (217mm) of precipitation.

What month is the ocean warmest in Sanibel?

With an average ocean temperature of 87.1°F (30.6°C), August is the month with the warmest seawater.

What is the most humid month in Sanibel?

The most humid month in Sanibel is December, with an average relative humidity of 77%.

What is the month with the shortest days in Sanibel?

With an average of 10h and 30min of daylight, December has the shortest days of the year in Sanibel, Florida.

What is the month with the least sunshine in Sanibel?

With an average of 6.6h of sunshine, December has the least sunshine of the year in Sanibel.

Average temperature
Sanibel, FL

Average temperature - Sanibel, FL

The warmest month (with the highest average high temperature) is August (88°F).
The month with the lowest average high temperature is January (69.8°F).

The month with the highest average low temperature is August (81.1°F).
The coldest month (with the lowest average low temperature) is January (59.5°F).

Average pressure
Sanibel, FL

Average pressure - Sanibel, FL

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is September (29.95"Hg).

Average wind speed
Sanibel, FL

Average wind speed - Sanibel, FL

The windiest months (with the highest average wind speed) are October and November (10.1mph).
The calmest month (with the lowest average wind speed) is July (6.9mph).

Average humidity
Sanibel, FL

Average humidity - Sanibel, FL

The month with the highest relative humidity is December (77%).
The months with the lowest relative humidity are March, May, July, August and October (73%).

Average rainfall
Sanibel, FL

Average rainfall - Sanibel, FL

The wettest month (with the highest rainfall) is August (8.54").
The driest month (with the least rainfall) is February (1.06").

Average rainfall days
Sanibel, FL

Average rainfall days - Sanibel, FL

The month with the highest number of rainy days is August (27.3 days).
The month with the least rainy days is February (8.2 days).

Average sea temperature
Sanibel, FL

Average sea temperature - Sanibel, FL

The best month for swimming (with the highest average sea temperature) is August (87.1°F).
The coldest month (with the lowest average sea temperature) is January (65.3°F).

Average daylight / Average sunshine
Sanibel, FL

Average daylight / Average sunshine - Sanibel, FL

The month with the longest days is June (Average daylight: 13h and 48min).
The month with the shortest days is December (Average daylight: 10h and 30min).

The month with the most sunshine is May (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 36min).

Average sunshine days
Sanibel, FL

Average sunshine days - Sanibel, FL

The month with the most sunshine days is January (19.8 days).
The month with the least sunshine days is August (2.3 days).

Average UV index
Sanibel, FL

Average UV index - Sanibel, FL

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 February (UV index 5).

Average visibility
Sanibel, FL

Average visibility - Sanibel, FL

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).

Sanibel, Florida, USA

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