Saint John Island Climate

Last updated: January 18, 2025

Saint John Island, part of the U.S. Virgin Islands, showcases a tropical savanna climate as classified by the Köppen-Geiger system (Am). Characterized by a warm and inviting atmosphere, the island experiences a mild minimum temperature of 22°C (72°F) in February, and an average temperature that hovers around 26°C (80°F). The conditions peak in September, with maximum temperatures reaching 29°C (85°F). This climate fosters lush ecosystems and creates ideal conditions for both residents and visitors alike to enjoy the stunning natural beauty of the island.

Saint John Island temperature by month

In Saint John Island, U.S. Virgin Islands, temperature patterns reveal a consistent warmth throughout the year, with only slight fluctuations between seasons. The year begins with pleasant conditions, where January and February feature minimum temperatures around 22-23°C (72-74°F) and average highs of 25-27°C (77-80°F). As spring transitions into summer, temperatures gradually rise, peaking in the warmer months of June through September, which present minimums of 25°C (77°F) and maximums reaching up to 29°C (85°F). Despite these warmer conditions, the averages remain comfortably in the 27-28°C (81-82°F) range. The fall months see a slight cooling, but temperatures remain mild, with averages of 26-27°C (79-81°F) in October and November. Overall, Saint John Island enjoys a tropical climate characterized by minimal temperature variation, making it a year-round destination for warmth and sunshine.

Monthly Temperatures in Saint John Island, Virgin Islands (U.S.)

The chart illustrates Saint John 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.
JanFebMarAprMayJunJulAugSepOctNovDec777777787981818282818079
Data source: Saint John 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.

Cruz Bay experiences a comfortable climate, with temperatures ranging from a minimum of 22°C (72°F) in February to a maximum of 29°C (85°F) in September. For more detailed information on the monthly temperatures in Cruz Bay, you can visit monthly temperatures in Cruz Bay.

Precipitation Patterns in Saint John Island

Saint John Island experiences a distinct precipitation pattern throughout the year, characterized by a rainy season that peaks during the late summer and early fall. From January to April, rainfall remains relatively low, ranging from 32 mm (1.2 in) to 39 mm (1.5 in), with an average of about 8-12 rainy days per month. However, as the climate warms into May and June, a noticeable increase in precipitation occurs, with totals climbing to 60 mm (2.4 in) and 61 mm (2.4 in), respectively, and additional rainy days reaching around 14-16.

The true height of the rainy season unfolds from July to October, with September being particularly notable, where 157 mm (6.2 in) of rain falls over 18 days. July and August also contribute significantly to this trend, with rainfall amounts of 93 mm (3.7 in) and 113 mm (4.4 in). Although October experiences a slight decrease to 133 mm (5.2 in), the overall pattern highlights the island's lush, tropical environment, supported by consistent rainfall that nourishes its vibrant ecosystems.

Monthly Average Precipitation in Saint John Island, Virgin Islands (U.S.)

The average monthly precipitation in Saint John Island, providing insights into seasonal rainfall patterns and the region's precipitation trends throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec3332373960619311315713310651
Data source: Saint John Island precipitation data aggregated from multiple regional locations, generated using Copernicus Climate Change Service information.
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Sunshine Duration in Saint John Island

Saint John Island, U.S. Virgin Islands, basks in abundant sunshine throughout the year, with notable variations that reflect seasonal trends. The sunniest months tend to be from March to May, where hours of sunshine peak impressively, reaching 350 hours in March and 358 hours in May. This period of bright, clear skies invites both tourists and locals to partake in outdoor activities. Even adjacent months like April and June maintain a robust sunshine record with 348 hours and 345 hours, respectively, underscoring the island's inviting climate as it transitions into the summer.

As summer progresses into fall, sunshine hours gradually diminish but remain substantial. July offers 355 hours, followed closely by August with 347 hours, before dipping further in September to 320 hours. The slight decrease in sunlight continues into October and November, with 316 hours and 304 hours, indicating the island's subtle shift toward its winter months. Despite these reductions, December still offers a commendable 321 hours, thereby ensuring that the allure of sunshine persists year-round. Overall, the consistent availability of sunlight contributes to Saint John Island's reputation as a tropical paradise, ideal for sun-seekers throughout all seasons.

Monthly Sunshine in Saint John Island, Virgin Islands (U.S.)

Monthly sunshine duration represents the total hours of direct sunlight Saint John Island receives each month, excluding periods when the sun is obscured by clouds or other obstructions.
JanFebMarAprMayJunJulAugSepOctNovDec258h299h350h348h358h345h355h347h320h316h304h321h
Data source: Saint John Island sunshine duration data aggregated from multiple regional locations, generated using Copernicus Climate Change Service information.

Saint John Island UV Index Trends

The UV Index in Saint John Island, U.S. Virgin Islands, reveals significant seasonal variations that highlight the intense sun exposure throughout the year. Beginning in January, the UV Index starts at a notable 9, categorized as very high, which translates to a burn time of just 15 minutes. However, as the year progresses, the UV levels escalate dramatically, with readings peaking at 14 in September, categorized as extreme and necessitating only 10 minutes of exposure before risking sunburn. The months of February through August consistently feature extreme UV Index levels of 11 to 13, emphasizing the need for sun protection during this period.

As autumn approaches, the UV Index begins to decline, yet remains elevated; October sees a reading of 12 before dropping to 9 in November, and finally 8 in December. Although these months are relatively safer compared to the summer peak, caution is still advised to prevent skin damage. Understanding the fluctuations in UV Index not only informs safe sun exposure practices but also underscores the importance of applying sunscreen and wearing protective clothing throughout the year in this sun-kissed paradise.

Monthly Maximum UV Index for Saint John Island, Virgin Islands (U.S.)

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Saint John Island. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec911131313131313141298
Data source: Saint John 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 Saint John Island

In Saint John Island, U.S. Virgin Islands, daylight duration demonstrates a relatively stable schedule throughout the year, with only slight variations aligning with the seasons. Both January and February enjoy approximately 11 hours of daylight, providing residents and visitors with ample time to bask in the island’s tropical ambiance. As spring arrives in March, daylight extends to 12 hours, maintaining this duration through April and May, which fosters vibrant outdoor activities amid the pleasant climate.

With the onset of summer in June and July, daylight peaks at 13 hours, offering the longest days of the year and ideal conditions for exploration and recreation. As summer transitions into fall, daylight begins to recede, returning to 12 hours in August and September, before falling back to 11 hours in October through December. This gradual adjustment in daylight duration illustrates the island's consistent climate, ensuring a sunny oasis year-round for those seeking adventure or relaxation under the sun.

Average Monthly Daylight Hours in Saint John Island, Virgin Islands (U.S.)

This chart shows the total daylight hours Saint John Island receives each month, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec669h692h722h753h779h791h785h762h732h701h675h662h
Data source: Saint John Island daylight hours, calculated based on aggregated data for various regional locations, determined by the times between sunrise and sunset.

Climate Highlights of Saint John Island's Popular Destinations

Cruz Bay, Virgin Islands (U.S.) enjoys a tropical climate characterized by warm temperatures year-round, with averages ranging from 25°C (77°F) in January to 28°C (82°F) in the summer months. Rainfall varies significantly, peaking at 157 mm (6.2 in) in September, while precipitation tends to be lower from January to April. Sunshine is abundant, with the highest hours recorded in May at 358 hours, ensuring plenty of bright days for outdoor activities. For more detailed climate information, visit Cruz Bay climate.

Conclusion

In conclusion, Saint John Island, U.S. Virgin Islands, stands out as a tropical haven characterized by its remarkable climate, consistent warmth, and abundant sunlight. The interplay of temperature, precipitation, UV Index, and daylight duration creates an inviting atmosphere for both nature enthusiasts and sun-seekers. With a steady rise in temperatures and sun exposure during the warmer months, paired with a vibrant ecosystem nourished by seasonal rainfall, the island offers an ideal escape year-round. Understanding these climatic patterns not only enhances appreciation for this stunning destination but also underscores the importance of sun safety and environmental awareness, ensuring that visitors can fully enjoy the unique beauty and experiences that Saint John Island has to offer.

Discover the Climate of Saint John Island's Places

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