Climate and monthly weather forecastSaint John, VI
Climate and monthly weather forecast
The climate of Saint John
Saint John, located in the United States Virgin Islands, is categorized under the Am—or Tropical Monsoon—Köppen climate classification. This climate is distinguished by heavy and frequent rainfall, and a relatively minor temperature shift throughout the year. Taking a look at the climate data, this Caribbean location proves to be a place of warmth and consistent rainfall under the tropical sun.Throughout the entire year, the island's temperature stays relatively constant, with only a slight spike in heat during the mid-year months. Monthly average high temperatures range from 82°F (27.8°C) at the start of the year, and tend to peak at 88°F (31.1°C) between the months of July to September. Minimum temperatures also follow a similar pattern, beginning at 70°F (21.1°C) and rising to 75°F (23.9°C) from May to October.
Rainfall is a prominent feature of Saint John's climate. The island witnesses precipitation throughout the year, with significant increases during the latter half. The quantity of rainfall starts at 2.7" (69mm) in January, and slowly increases to reach a high point of 6.3" (160mm) in the months of October and November. Concurrently, the number of rainfall days also increase, starting with 10 days in February and March, to a max of 16 days in September and October.
The daylight hours fluctuate, starting at 11.2 hours per day in January, and peaking at 13.2 hours in June and July. Correspondingly, the hours of sunshine also wax and wane from 8 hours at the start and end of the year to 9 hours between March to July and then back.
The best time to visit Saint John
Qualifying the best time to visit Saint John is contingent on weather preferences and tolerance for rainfall. Based on temperature and rainfall data, the most favorable period to experience Saint John would arguably be between March and May. During these months, the high temperatures range from 82°F (27.8°C) to 84°F (28.9°C), while the low temperatures fluctuate between 70°F (21.1°C) to 72°F (22.2°C). This period offers ample sunshine and a relatively lower rainfall accumulation, ranging from 2.2" (56mm) to 3.5" (89mm).The worst time to visit Saint John
The least ideal time to visit Saint John would be during the late summer and autumn months, particularly from August to November. This period is characterized by heavier rainfall, with monthly averages fluctuating from 4.9" (124mm) to 6.3" (160mm), and a greater number of rainy days, measuring from 14 to 16 days per month. This excessive rain might limit outdoor activities and sightseeing opportunities.Spring weather in Saint John
Springtime in Saint John from March through May offers moderate temperatures. Maximum temperatures average between 82°F (27.8°C) and 84°F (28.9°C), while minimum averages revolve around 70°F (21.1°C) to 73°F (22.8°C). Along with these pleasant temperatures, the area experiences between 2.2" (56mm) and 5.1" (130mm) of rainfall, with rainfall days varying from 10 to 12.Summer weather in Saint John
Summertime from June to August in Saint John leans towards warmer temperatures and high rainfall. Peak temperatures range from 86°F (30°C) to 88°F (31.1°C), while the lower limit remains around a steady 75°F (23.9°C). Rainfall during this season ranges from 2.9" (74mm) to 4.9" (124mm), and the number of rainy days increases to 14 by August.Autumn weather in Saint John
Autumn in Saint John brings more rainfall and mild temperature shifts. From September to November, high temperatures shift down slightly, fluctuating between 86°F (30°C) and 84°F (28.9°C). The average minimum temperature remains steady at 75°F (23.9°C) in September and October, moving down to 73°F (22.8°C) in November. Rainfall sees a prominent increase, with measurements varying from 5.6" (142mm) to 6.3" (160mm).Winter weather in Saint John
Winter in Saint John spans December to February, continuing with mild temperatures and decreasing rainfall. High temperatures follow a downward trend from 82°F (27.8°C) to 82°F (27.8°C), and low temperatures range between 72°F (22.2°C) and 70°F (21.1°C). These months also see a relatively drier period; rainfall averages decrease to between 2.7" (69mm) and 2.1" (53mm), distributed over 14 to 10 days.Weather in January
Saint John ushers in the year with typically maritime tropical weather, featuring warm temperatures, ample sun, moderate rain. Moving from December, the city witnesses little fluctuation, both in the degree of temperatures and rainfall. Weather in January »Weather in February
As Saint John moves into February, the subtle shift in climate bears resemblance to January. The temperate maritime weather, accompanied by a pleasant sea breeze, makes outdoor activities enjoyable for residents and tourists alike. Weather in February »Weather in March
The arrival of March in Saint John marks a minor transition from February. The weather changes balance out, offering more daylight hours and increased sunshine. Out of all standout weather characteristics in March, an increase in UV index up to 12 alongside 2.2" (56mm) of rainfall paints a clear picture of a typical March weather pattern. Weather in March »Weather in April
Navigating from March, April in Saint John witnesses moderate changes. The city continues its journey through the year maintaining its tropical climate characteristics, with a slight rise in temperatures making for a warmer month. Weather in April »Weather in May
May brings a subtle warm up to the Virgin Islands' Saint John. The gentle rise in temperature when paired with sea breezes makes May weather a delightful experience for beach goers and sightseers. Despite it being a warm month, the significant weather change is, May receives the heaviest rainfall so far in the year, at 5.1" (130mm). Weather in May »Weather in June
Combining the languid ambiance of summer with tropical weather, June in Saint John presents a warm and inviting climate. Transitioning from May, the weather sees a minor upsurge in temperatures, alongside mostly clear skies to bask in. Weather in June »Weather in July
July ushers in the height of summer in Saint John with greater warmth and humidity. The tropical climate becomes intense, drawing visitors to the cool, azure waters. While temperatures edge up slightly, the standout figure is that July shares 3.3" (84mm) of rainfall with June. Weather in July »Weather in August
August moves in with similar weather conditions to July, maintaining a warm and humid climate in Saint John. The tropical city welcomes visitors seeking the warm waters and abundant sunshine during this summertime. August does ramp up its rainfall, reaching 4.9" (124mm). Weather in August »Weather in September
Despite heading towards the tail end of summer, September in Saint John brings no reprieve from the warmth. The tropical maritime climate is at its zenith during this period, with plenty of sun-soaked days to enjoy. The high point featuring September weather is the substantial increase in rainfall, registering a notable 5.6" (142mm). Weather in September »Weather in October
The arrival of October in Saint John signifies the subtle beginning of the transition away from the intense summer season. While the climate retains its warmth, there is a gentle cooling effect as the month progresses. October is characterized by 6.3" (160mm) of rainfall, marking the year’s highest, making it the wettest month. Weather in October »Weather in November
As the year nears its end, November brings slight shifts in Saint John's climate. The city witnesses a slow dip in temperatures as the month marks the onset of the cooler months. Despite decreasing temperatures, November shares the same amount of rainfall as October, standing at 6.3" (160mm). Weather in November »Weather in December
Closing the year, December in Saint John brings the cool breath of winter mixed with a tropical climate. The slower pace of the city matches the gentle coolness in the air. While the temperature sees a minor dip, December’s significant change lies in its reduced rainfall, going down to 4.7" (119mm). Weather in December »Updated: Jul 9, 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
The months of January through March and December bring the lowest temperatures, averaging a high of 82.4°F (28°C).
In Saint John, during the entire year, the rain falls for 156 days and collects up to 49.69" (1262mm) of precipitation.
The months with the coldest seawater in Saint John are January through April, with an average ocean temperature of 78.8°F (26°C).
The month with the least rainfall is February, when the rain falls for 10 days and typically collects 2.13" (54mm) of precipitation.
The months with the most sunshine are March, April, July and August, with an average of 9h of sunshine.
The months with the highest UV index in Saint John are March through September, with an average maximum UV index of 12.
With an average of 13h and 12min of daylight, June has the longest days of the year.
The warmest period falls in August and September, when the average high-temperature reaches 87.8°F (31°C).
September and October, with an average ocean temperature of 84.2°F (29°C), are months with the warmest seawater.
The months with the most rainfall are October and November, with an average 6.34" (161mm) of precipitation.
November and December, with an average of 7h of sunshine, are months with the least sunshine.
With an average of 11h and 6min of daylight, December has the shortest days of the year.
Saint John does not observe Daylight Saving Time (DST). AST timezone is used throughout the entire year.
The month with the lowest UV index is December, with an average maximum UV index of 7.
Average temperature
Saint John, VI
The warmest months (with the highest average high temperature) are August and September (88°F).
The months with the lowest average high temperature are January, February, March and December (82°F).
The months with the highest average low temperature are June, July, August, September and October (75°F).
The coldest months (with the lowest average low temperature) are January, February and March (70°F).
Average rainfall
Saint John, VI
The wettest months (with the highest rainfall) are October and November (6.3").
The driest month (with the least rainfall) is February (2.1").
Average rainfall days
Saint John, VI
- Average rainfall days in January:
14 days - Average rainfall days in February:
10 days - Average rainfall days in March:
10 days - Average rainfall days in April:
9 days - Average rainfall days in May:
12 days - Average rainfall days in June:
12 days
- Average rainfall days in July:
14 days - Average rainfall days in August:
14 days - Average rainfall days in September:
16 days - Average rainfall days in October:
16 days - Average rainfall days in November:
15 days - Average rainfall days in December:
14 days
The months with the highest number of rainy days are September and October (16 days).
The month with the least rainy days is April (9 days).
Average sea temperature
Saint John, VI
The best months for swimming (with the highest average sea temperature) are September and October (84°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (79°F).
Average daylight / Average sunshine
Saint John, VI
- Average daylight in January:
11h and 12min - Average daylight in February:
11h and 36min - Average daylight in March:
12h and 6min - Average daylight in April:
12h and 36min - Average daylight in May:
13h and 0min - Average daylight in June:
13h and 12min
- Average daylight in July:
13h and 6min - Average daylight in August:
12h and 42min - Average daylight in September:
12h and 12min - Average daylight in October:
11h and 42min - Average daylight in November:
11h and 18min - Average daylight in December:
11h and 6min
The month with the longest days is June (Average daylight: 13h and 12min).
The month with the shortest days is December (Average daylight: 11h and 6min).
The months with the most sunshine are March, April, July and August (Average sunshine: 9h).
The months with the least sunshine are November and December (Average sunshine: 7h).
Average UV index
Saint John, VI
The months with the highest UV index are March, April, May, June, July, August and September (UV index 12).
The month with the lowest UV index is December (UV index 7).
