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Contents
- The climate of Portsmouth
- The best time to visit Portsmouth
- The worst time to visit Portsmouth
- Spring weather in Portsmouth
- Summer weather in Portsmouth
- Autumn weather in Portsmouth
- Winter weather in Portsmouth
- 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 rainfall
- Average rainfall days
- Average sea temperature
- Average daylight
- Average sunshine
- Average UV index
The climate of Portsmouth
Portsmouth, Dominica features a tropical rainforest climate, referred to as Af within the Köppen climate classification, the most widely used climate classification system. Located in the northern region of the island, this city bears witness to high temperatures and heavy rainfall all year round.
Temperature averages remain consistently high, fluctuating on a minute scale from 21°C (69.8°F) to 24°C (75.2°F) for low temperatures, and a marginally wider scale from 28°C (82.4°F) to 31°C (87.8°F) for high temperatures. Rainfall levels demonstrate a similar pattern, staying relatively steady throughout the year, but showing a gradual increase from the beginning of the year, from 95mm (3.74") in February, peaking at 300mm (11.81") in November, and then dropping slightly to 201mm (7.91") by December.
A prevalent feature of Portsmouth's weather is the higher than average number of rainfall days per month, ranging from 14 to 22 days. Consequently, despite boasting ample daylight hours - a steady 11.3 hours in January, slowly rising to a peak of 13 hours in June and then declining back to 11.2 hours by December - the amount of sunshine received is significantly less. On average, Portsmouth enjoys between 6 and 8 hours of sunshine per day.
UV index values hover between a minimum of 8 in December and a maximum of 12 from March to September, indicating a high level of ultraviolet radiation throughout the year. Sea temperatures, much like the ambient ones, remain relatively stable, ascending through the first nine months before decreasing slightly, with a range from 26.7°C (80.1°F) in February to 29.4°C (84.9°F) in September.
Temperature averages remain consistently high, fluctuating on a minute scale from 21°C (69.8°F) to 24°C (75.2°F) for low temperatures, and a marginally wider scale from 28°C (82.4°F) to 31°C (87.8°F) for high temperatures. Rainfall levels demonstrate a similar pattern, staying relatively steady throughout the year, but showing a gradual increase from the beginning of the year, from 95mm (3.74") in February, peaking at 300mm (11.81") in November, and then dropping slightly to 201mm (7.91") by December.
A prevalent feature of Portsmouth's weather is the higher than average number of rainfall days per month, ranging from 14 to 22 days. Consequently, despite boasting ample daylight hours - a steady 11.3 hours in January, slowly rising to a peak of 13 hours in June and then declining back to 11.2 hours by December - the amount of sunshine received is significantly less. On average, Portsmouth enjoys between 6 and 8 hours of sunshine per day.
UV index values hover between a minimum of 8 in December and a maximum of 12 from March to September, indicating a high level of ultraviolet radiation throughout the year. Sea temperatures, much like the ambient ones, remain relatively stable, ascending through the first nine months before decreasing slightly, with a range from 26.7°C (80.1°F) in February to 29.4°C (84.9°F) in September.
The best time to visit Portsmouth
Given the city's unvarying climate, the best time to visit Portsmouth hinges on individual preferences. However, for those seeking to enjoy the highest possible temperatures, the period from May to September offers the highest average temperatures, reaching 31°C (87.8°F). During this time, the average sea temperature also peaks, reaching a comfortable 29.4°C (84.9°F) in September.
For individuals who prefer moderate rainfall, the period from February to April, usually sees lower rainfall levels, fluctuating between 95mm (3.74") to 105mm (4.13") accompanied by fewer rainfall days between 14 to 15 days per month. The UV index during this period is also at its highest, hitting a maximum of 12, indicating clear, sunny skies.
For individuals who prefer moderate rainfall, the period from February to April, usually sees lower rainfall levels, fluctuating between 95mm (3.74") to 105mm (4.13") accompanied by fewer rainfall days between 14 to 15 days per month. The UV index during this period is also at its highest, hitting a maximum of 12, indicating clear, sunny skies.
The worst time to visit Portsmouth
Travellers seeking to avoid peak rainfall should steer clear of visiting Portsmouth from September to November when the rainfall reaches its zenith, spanning from 269mm (10.59") to 300mm (11.81"). Correspondingly, rainfall days also peak during this stretch of the year, ranging from 19 to 22 days per month.
Despite these increased rainfall levels, temperatures remain relatively high, averaging at 30°C (86°F), and the sea temperatures are still warm, maintaining an average of 29°C (84.2°F). The UV index starts to drop from September onwards, reaching its lowest level in December.
Despite these increased rainfall levels, temperatures remain relatively high, averaging at 30°C (86°F), and the sea temperatures are still warm, maintaining an average of 29°C (84.2°F). The UV index starts to drop from September onwards, reaching its lowest level in December.
Spring weather in Portsmouth
In Portsmouth, spring unfolds from March to May. During this period, the city's average high temperatures climb from 29°C (84.2°F) to 30°C (86°F), while the average low temperatures ascend from 21°C (69.8°F) to 23°C (73.4°F). Rainfall in spring varies from 95mm (3.74") to 177mm (6.97"), and the corresponding number of rainfall days also increases from 14 to 17. The sea's warmth also increases gradually throughout spring from 26.9°C (80.4°F) to 28°C (82.4°F).
Summer weather in Portsmouth
Summer in Portsmouth spans June to August. As expected, this season brings the hottest weather in Portsmouth with high temperatures consistently recorded at 31°C (87.8°F). Sea temperatures also reach their peak during this season, rising from 28.4°C (83.1°F) in June to a balmy 29°C (84.2°F) in August. Rainfall gradually increases from 173mm (6.81") to 243mm (9.57"), accompanied by an uptick in the number of rainfall days from 18 to 20. However, daylight and sunshine hours remain virtually unchanged.
Autumn weather in Portsmouth
September to November is autumn in Portsmouth. During this season, high temperatures hold steady at 30°C (86°F), while low temperatures decrease marginally from 24°C (75.2°F) to 22°C (71.6°F). Autumn emerges as Portsmouth's wettest season, with rainfall levels rising sharply from 269mm (10.59") in September to 300mm (11.81") in November. Correspondingly, the number of rainfall days also escalates, topping at 22 in September.
Winter weather in Portsmouth
Winter in Portsmouth, spanning December to February, experiences average high temperatures that range from 28°C (82.4°F) to 29°C (84.2°F), while low temperatures fluctuate between 21°C (69.8°F) and 22°C (71.6°F). In terms of rainfall, December begins with a relative deluge of 201mm (7.91"), but levels drop substantially to reach 95mm (3.74") by February. The sea, cooling from its summer warmth, dips to 27.6°C (81.7°F) in December and reaches its lowest temperature of 26.7°C (80.1°F) in February. Despite fewer daylight and sunshine hours, winter also sees a significant decline in the UV index, with readings decreasing from 8 in December to 9 in February.
Weather in January
Portsmouth, Dominica greets the year with considerably wet weather in January. This significant rainfall can create a distinctly humid atmosphere. On average, precipitation amounts to 144mm (5.67") across 18 days. Maritime influences result in mild sea temperatures, providing a soft and enjoyable environment for water activities. Weather in January »
Weather in February
Enjoying close proximity to the Equator, Portsmouth maintains a consistently high UV index throughout February, reaching 11. Slightly less rainfall graces the island at this time, leading into the drier month of March. Despite the lesser precipitation, the city remains humid, though not unbearable. Weather in February »
Weather in March
In March, Portsmouth begins to see an increment in daylight hours. Conditions are optimal for sunbathing and sightseeing, given the increase in sunlight. With an average of 110mm (4.33") over 15 days, rainfall decreases significantly compared to the preceding months of January and February. Weather in March »
Weather in April
April in Portsmouth marks the advent of a slightly wetter weather pattern. Sudden, brisk rain showers can be part of the day, though they are usually short-lived. Recorded sea temperatures average around 27.6°C (81.7°F), making it perfect for water-based activities. Weather in April »
Weather in May
May in Portsmouth is characterized by a noticeable increase in rainfall, with average precipitation amounts rising to 177mm (6.97"). High temperatures beckon beach-goers as the sea's warmth hits its peak. Daylight hours extend, illuminating the city longer and offering extended periods for exploring. Weather in May »
Weather in June
June sets the stage for the official hurricane season in Portsmouth. On record, average sunshine hours hold steady at 8 hours per day. As one of the months with heaviest rainfall, June receives an impressive 173mm (6.81") precipitation on average. Weather in June »
Weather in July
Portsmouth experiences peak rainfall in July, with the average precipitation rising to 156mm (6.14"). The sea temperature soars to 28.7°C (83.7°F), which, along with stable sunlight hours, makes any beach day inviting. Despite the wet environment, it offers a good blend of warm weather and vibrant tropical energy. Weather in July »
Weather in August
August sets in, with Portsmouth witnessing its highest recorded monthly rainfall average of 243mm (9.57"). The UV index rating, while still high at 12, necessitates suitable sun protection for skin health. Noteworthy is the steady sea temperature, providing warm conditions for water enthusiasts. Weather in August »
Weather in September
September nudges ahead to claim the wettest month title in Portsmouth, accumulating an average rainfall of 269mm (10.59"). Daylight hours slightly decrease, reflecting autumn's approach. Despite the climatic shift, the sea temperature maintains a warm average, catering to water activities. Weather in September »
Weather in October
With October, Portsmouth steps into its most humid month of the year. The UV index now stands at 11, a slight decrease from the September rating. It retains September's precipitation pattern, with an average rainfall of 279mm (10.98"). Weather in October »
Weather in November
November marks the close of the official hurricane season in Portsmouth. Meteorological patterns in this period exhibit a steep decline in average rainfall, hitting 300mm (11.81") per month. While rain showers are less frequent, they're more intense when they do happen. Weather in November »
Weather in December
In December, Portsmouth braces for a substantial decrease in the number of daylight hours, dropping to an average of 11.2. The city experiences a notable reduction in rainfall when compared to November, receiving roughly 201mm (7.91") of rainfall. Weather in December »
[Resources]Frequently asked questions
What is the coldest month in Portsmouth?
Portsmouth's temperature records reveal January as the coldest month, marked by average highs of 28°C (82.4°F) and lows of 21°C (69.8°F).
How much does it rain in Portsmouth?
Throughout the year, in Portsmouth, Dominica, there are 214 rainfall days, and 2252mm (88.66") of precipitation is accumulated.
What is the driest month in Portsmouth?
February is the month with the least rainfall in Portsmouth. Rain falls for 14 days and accumulates 95mm (3.74") of precipitation.
When is the sea coldest in Portsmouth?
February is the month with the coldest seawater in Portsmouth, with an average sea temperature of 26.7°C (80.1°F).
What are the months with the most sunshine in Portsmouth?
March through August, with an average of 8h of sunshine, are months with the most sunshine in Portsmouth.
When is the highest UV index in Portsmouth?
March through September, with an average maximum UV index of 12, are months with the highest UV index in Portsmouth, Dominica.
What time of the year is the hottest in Portsmouth?
Portsmouth experiences peak temperatures, averaging a high-temperature of 31°C (87.8°F) during June through September.
When are the longest days in Portsmouth?
June has the longest days of the year in Portsmouth, with an average of 13h and 0min of daylight.
What month is the sea warmest in Portsmouth?
With an average sea temperature of 29.4°C (84.9°F), September is the month with the warmest seawater in Portsmouth, Dominica.
What is the wettest month in Portsmouth?
The month with the most rainfall in Portsmouth, Dominica, is November, when the rain falls for 19 days and typically aggregates up to 300mm (11.81") of precipitation.
What is the month with the shortest days in Portsmouth?
The month with the shortest days in Portsmouth, Dominica, is December, with an average of 11h and 12min of daylight.
Is there Daylight Saving Time (DST) in Portsmouth?
Portsmouth, Dominica, does not observe Daylight Saving Time (DST). AST timezone is used throughout the entire year.
What is the month with the least sunshine in Portsmouth?
The month with the least sunshine is December, with an average of 6h of sunshine.
When is the lowest UV index in Portsmouth?
December is the month with the lowest UV index in Portsmouth, with an average maximum UV index of 8.
Average temperature
Portsmouth, Dominica
The warmest months (with the highest average high temperature) are June, July, August and September (31°C).
The month with the lowest average high temperature is January (28°C).
The months with the highest average low temperature are July, August and September (24°C).
The coldest months (with the lowest average low temperature) are January, February and March (21°C).
Average rainfall
Portsmouth, Dominica
- Average rainfall in January:
144mm - Average rainfall in February:
95mm - Average rainfall in March:
110mm - Average rainfall in April:
105mm - Average rainfall in May:
177mm - Average rainfall in June:
173mm
- Average rainfall in July:
156mm - Average rainfall in August:
243mm - Average rainfall in September:
269mm - Average rainfall in October:
279mm - Average rainfall in November:
300mm - Average rainfall in December:
201mm
The wettest month (with the highest rainfall) is November (300mm).
The driest month (with the least rainfall) is February (95mm).
Average rainfall days
Portsmouth, Dominica
- Average rainfall days in January:
18 days - Average rainfall days in February:
14 days - Average rainfall days in March:
15 days - Average rainfall days in April:
14 days - Average rainfall days in May:
17 days - Average rainfall days in June:
18 days
- Average rainfall days in July:
20 days - Average rainfall days in August:
20 days - Average rainfall days in September:
22 days - Average rainfall days in October:
19 days - Average rainfall days in November:
19 days - Average rainfall days in December:
18 days
The month with the highest number of rainy days is September (22 days).
The months with the least rainy days are February and April (14 days).
Average sea temperature
Portsmouth, Dominica
The best month for swimming (with the highest average sea temperature) is September (29.4°C).
The coldest month (with the lowest average sea temperature) is February (26.7°C).
Average daylight / Average sunshine
Portsmouth, Dominica
- Average daylight in January:
11h and 2min - Average daylight in February:
11h and 4min - Average daylight in March:
12h and 1min - Average daylight in April:
12h and 3min - Average daylight in May:
12h and 5min - Average daylight in June:
13h and 0min
- Average daylight in July:
12h and 5min - Average daylight in August:
12h and 4min - Average daylight in September:
12h and 1min - Average daylight in October:
11h and 5min - Average daylight in November:
11h and 2min - Average daylight in December:
11h and 1min
The month with the longest days is June (Average daylight: 13h and 0min).
The month with the shortest days is December (Average daylight: 11h and 12min).
The months with the most sunshine are March, April, May, June, July and August (Average sunshine: 8h).
The month with the least sunshine is December (Average sunshine: 6h).
Average UV index
Portsmouth, Dominica
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 8).
Portsmouth, Dominica
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