Sister Island Climate

Last updated: January 18, 2025

The climate of Sister Island in the Cayman Islands is classified under the Köppen-Geiger system as Aw, indicative of a tropical savanna environment. Temperatures exhibit minimal seasonal variation, with a cool minimum of approximately 20°C (69°F) in January, gradually rising to an average of 27°C (81°F) throughout the year. The peak temperature is reached in July, climbing to a warm 31°C (88°F). This consistent warmth, coupled with its tropical nature, contributes to the island’s lush biodiversity and vibrant ecosystems.

Sister Island temperature by month

Sister Island in the Cayman Islands experiences a warm tropical climate with relatively stable temperature patterns throughout the year. The year begins with cooler temperatures in January, where minimums drop to 20°C (69°F) before gradually rising. By July, the island reaches its peak warmth, with maximum temperatures soaring to 31°C (88°F). Throughout the spring and summer months, average temperatures hover around 26°C to 29°C (78°F to 84°F), fostering a balmy atmosphere popular among visitors. As autumn arrives, temperatures begin to retreat slightly, yet remain mild, with December showcasing a minimum of 22°C (72°F). This consistent warmth, punctuated by only slight seasonal shifts, characterizes the inviting climate of Sister Island.

Monthly Temperatures in Sister Island, Cayman Islands

The chart illustrates Sister Island's temperature patterns throughout the year, with values aggregated from various locations across the region. It highlights seasonal variations and temperature changes across the months.
JanFebMarAprMayJunJulAugSepOctNovDec787878798182838483828179
Data source: Sister Island temperature data aggregated from multiple regional locations, generated using Copernicus Climate Change Service information.
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The average of daily temperatures (24 hours) calculated across all days in the month.

Little Cayman experiences mild weather throughout the year, with January temperatures averaging a minimum of 20°C (69°F) and rising to a maximum of 31°C (88°F) in July. This tropical climate makes it an inviting destination for visitors year-round. For more detailed information, you can check the monthly temperatures in Little Cayman.

Precipitation Patterns in Sister Island

Sister Island experiences a distinct precipitation pattern characterized by varying rainfall amounts throughout the year. Post the drier winter months of January, February, and March, which see only 36 mm (1.4 in), 25 mm (1.0 in), and 19 mm (0.8 in) respectively, April sees a slight increase to 35 mm (1.4 in). However, the real shift occurs in May, when rainfall surges to 131 mm (5.2 in), marking the onset of the wet season. This month is followed by a series of wet months, culminating in October, which is the wettest month at 229 mm (9.0 in).

Rainfall frequency also increases significantly as the year progresses; while the early months see only a handful of wet days, the late summer and autumn months see much more. May has an average of 18 rainy days, with this number peaking in October at 23 days. Such rainfall patterns are pivotal for the island's ecosystems and contribute to the lush landscapes that the Cayman Islands are known for, ultimately establishing a clear contrast between the dry winter season and the rainier summer months.

Monthly Average Precipitation in Sister Island, Cayman Islands

The average monthly precipitation in Sister Island, providing insights into seasonal rainfall patterns and the region's precipitation trends throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec3625193513261521179722916038
Data source: Sister Island precipitation data aggregated from multiple regional locations, generated using Copernicus Climate Change Service information.
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Sunshine Duration in Sister Island

Sister Island boasts a delightful sunshine profile, characterized by a steady increase in sunlight hours from winter to summer. Beginning with 248 hours of sunshine in January, the island experiences a gradual rise through the early months of the year, culminating in 341 hours by March and peaking at 343 hours in April. These months offer ample sun, making them ideal for visitors seeking to bask in warm tropical rays. Even as the rainy season approaches in late spring and summer, sunshine remains abundant, with June and July boasting 324 hours and 352 hours, respectively, marking July as the sunniest month of the year.

As summer transitions to autumn, sunshine hours show a slight decline but remain generous. August continues to provide 337 hours of sunshine, while September and October feature 325 hours and 304 hours. The waning sunlight is complemented by the humid and sometimes rainy conditions typical of the season. By November, sunshine dips to 287 hours, followed by 300 hours in December, signaling a return to the sunnier conditions of winter. Overall, the island's sunshine trends highlight its appeal as a year-round destination, with peak sun-laden months ideally suited for sun seekers and outdoor enthusiasts alike.

Monthly Sunshine in Sister Island, Cayman Islands

Monthly sunshine duration represents the total hours of direct sunlight Sister Island receives each month, excluding periods when the sun is obscured by clouds or other obstructions.
JanFebMarAprMayJunJulAugSepOctNovDec248h298h341h343h332h324h352h337h325h304h287h300h
Data source: Sister Island sunshine duration data aggregated from multiple regional locations, generated using Copernicus Climate Change Service information.

Sister Island UV Index Trends

The UV Index on Sister Island indicates a significant risk of harm from unprotected sun exposure throughout the year, with values predominantly falling within the very high to extreme categories. January begins with a UV Index of 8, classified as very high, and burn time limited to 15 minutes. However, as the year progresses into late winter and early spring, the UV Index escalates rapidly, peaking in April and May at 13, where the exposure category remains extreme, and the burn time shortens to just 10 minutes. This trend underscores the growing intensity of sun exposure in the lead-up to summer.

From June to October, the UV Index remains consistently high, hovering around 12 to 13 and solidifying the extreme classification during the peak sunshine months. Visitors should exercise caution, as the burn time stays at a mere 10 minutes during these months. Following October, the index gradually decreases, with November and December marked at 9 and 8 respectively, indicating a return to very high levels but with slightly longer burn times of 15 minutes. Effectively, this data highlights the necessity for adequate sun protection measures, especially during the peak UV Index months when the risk of skin damage is substantial.

Monthly Maximum UV Index for Sister Island, Cayman Islands

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Sister Island. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec811121313131212121198
Data source: Sister Island UV Index data aggregated from multiple regional locations, generated using Copernicus Climate Change Service information.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

Daylight Hours in Sister Island

Daylight duration on Sister Island exhibits a subtle yet noticeable seasonal variation, providing a balanced experience of light throughout the year. Winter months, specifically January and February, feature around 11 hours of daylight, creating a picturesque setting for leisurely activities. As spring approaches, March and April see a slight increase, with daylight extending to 12 hours. This gradual transition marks the onset of longer days, which peaks in late spring and early summer, where May, June, and July enjoy the maximum daylight of 13 hours.

As summer wanes towards autumn, daylight duration starts to recede, but still maintains a moderate amount of light. August and September both offer 12 hours of daylight, before the transition back to 11 hours in October and November. By December, daylight shortens further to 10 hours, ushering in the shorter days of winter. This rhythmic cycle of daylight duration not only contributes to the island's charm but also supports a vibrant array of outdoor activities throughout the year, encouraging both residents and visitors to take advantage of the sunlit hours.

Average Monthly Daylight Hours in Sister Island, Cayman Islands

This chart shows the total daylight hours Sister Island receives each month, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec664h689h722h755h783h797h789h764h733h699h671h657h
Data source: Sister Island daylight hours, calculated based on aggregated data for various regional locations, determined by the times between sunrise and sunset.

Climate Highlights of Sister Island's Popular Destinations

Little Cayman, Cayman Islands, boasts a tropical climate characterized by warm temperatures year-round, with average monthly highs ranging from 26°C (78°F) in January to 29°C (84°F) in July and August. The region experiences its heaviest rainfall in October, with 229 mm (9.0 in), while the driest months are March and February, receiving only 19 mm (0.8 in) and 25 mm (1.0 in) respectively. Sunshine is abundant, particularly in the summer, with July averaging 352 hours of sunlight. For more details on the climate, visit Little Cayman climate.

Conclusion

In conclusion, Sister Island, Cayman Islands, presents a captivating climate characterized by warm temperatures, abundant sunshine, and varying precipitation patterns, all of which contribute to its allure as a tropical paradise. With an annual cycle that showcases the intensity of sunlight and UV exposure, particularly during the summer months, awareness and protection against sun-related risks become vital for residents and visitors alike. As daylight duration fluctuates throughout the year, individuals can plan their activities to take full advantage of the island's natural beauty. Ultimately, the unique climate of Sister Island encapsulates the essence of a serene yet vibrant environment, inviting exploration and enjoyment year-round.

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