Last updated: January 18, 2025
Saint John, Dominica, embodies a tropical rainforest climate as classified by the Köppen-Geiger system (Af). With a minimum temperature averaging around 22°C (72°F) in February, it offers a warm and inviting atmosphere year-round. The average temperature hovers around 26°C (79°F), providing a consistently pleasant environment. The locale reaches its maximum temperature of approximately 29°C (84°F) in September, illustrating the warmth characteristic of the region. This climate fosters lush vegetation, enhancing the natural beauty and biodiversity of Saint John.
In Saint John, Dominica, temperature patterns reveal a tropical warmth that gradually intensifies throughout the year. Starting with mild temperatures in January and February, where minimums range from 22°C (72°F) to 23°C (73°F) and averages around 25°C (77°F), conditions remain comfortable. As spring progresses into early summer, temperatures begin to rise slightly, with average highs peaking at 27°C (81°F) in typical summer months such as July and August. The maximum temperatures reach their zenith at 29°C (84°F) in both August and September, coinciding with the peak of the warm season. As autumn sets in, temperatures stabilize, maintaining a consistent warmth before dipping slightly by December. Overall, the climate of Saint John showcases a warm, tropical pattern with minimal fluctuations, fostering a year-round inviting environment.
In Portsmouth, February temperatures range from a mild minimum of 22°C (72°F) to a warm maximum of 29°C (84°F) in September, showcasing the tropical climate of the region. For more detailed temperature information, you can visit monthly temperatures in Portsmouth.
In Saint John, Dominica, precipitation showcases a distinct seasonal pattern, with noticeable increases during the summer months. The year begins with relatively low rainfall, averaging 35 mm (1.4 in) each month from January through March, highlighting a dry period where precipitation occurs over 12 to 14 days. As spring transitions into summer, precipitation begins to climb, with June recording 66 mm (2.6 in), followed by a significant jump in July to 91 mm (3.6 in), illustrating the onset of the wet season.
The peak of the rainy season occurs in late summer and early fall, with August and September experiencing the highest monthly totals of 112 mm (4.4 in) and 118 mm (4.6 in), respectively. October follows closely, with 122 mm (4.8 in), reflecting the enduring influence of tropical weather patterns. Despite a decrease in November and December, which see 99 mm (3.9 in) and 56 mm (2.2 in) of rain, the overall trend demonstrates a clear monsoonal climate with distinct wet and dry periods, sustaining the vibrant ecosystems characteristic of the region.
In Saint John, Dominica, sunshine duration exhibits a clear seasonal trend, with hours of sunlight steadily increasing from winter through early summer. Starting the year with 267 hours in January, the days gradually become brighter as spring arrives, culminating in March with an impressive 347 hours of sunshine. April and May maintain this upward trajectory, peaking at 359 hours in May, which marks the sunniest month of the year. This gradual rise not only enhances the warmth but also supports the lush vegetation that the region is known for.
As summer unfolds, sunshine hours remain abundant, with June showcasing 332 hours and July following closely at 355 hours. The days gradually shorten as the year progresses into late summer and autumn, yet even September, October, and November retain a respectable range from 318 to 321 hours, demonstrating that sunlight is still generous during these months. By December, sunshine duration slightly dips to 329 hours, indicating a gradual transition back to shorter days. Overall, the climate of Saint John benefits from a rich allocation of sunshine throughout the year, creating an inviting atmosphere for both residents and visitors alike.
Saint John, Dominica, is known for its notably high UV Index, particularly during the peak months from February to July, where numbers frequently reach 11 to 14, classified as extreme. This thriving tropical region experiences the highest UV Index of 14 in both April and May, reflecting not only the intensity of sunlight during the spring but also emphasizing the importance of sun protection. With burn times hovering around 10 minutes during extreme periods, it is crucial for residents and visitors alike to take precautions, such as wearing sunscreen and protective clothing to mitigate the risks associated with excessive UV exposure.
As the year progresses into late summer and autumn, the UV Index slightly decreases but remains significant, ranging from 12 to 13. In October, the UV Index is recorded at 12, while November and December see a reduction to 10 and 9, respectively, both categorized as very high. Despite this decline, the potential for sunburn persists, especially during midday hours. Understanding the UV Index is vital for enjoying outdoor activities safely, ensuring that the sun's powerful rays do not compromise the health of those who bask in the beauty of Saint John's tropical landscape.
UV Risk Categories
In Saint John, Dominica, daylight duration experiences subtle fluctuations throughout the year, starting with 11 hours of daylight in January and February. This consistent daylight provides a stable structure for daily activities and is ideal for enjoying the region's lush landscapes. As spring unfolds in March, daylight begins to extend to 12 hours, a trend that continues through April and May, enhancing outdoor experiences and promoting an active lifestyle.
The longest days occur in June, with 13 hours of daylight, marking the peak of summer. Following this, daylight gradually shifts back to 12 hours in July and remains consistent until October. As autumn approaches, daylight decreases again to 11 hours in November and December, creating a rhythmic cycle that aligns with the tropical climate. This variation in daylight hours contributes to the vibrant and dynamic ecosystem of Saint John, allowing both residents and visitors ample opportunity to explore the natural beauty of Dominica under the sun.
Portsmouth, Dominica experiences a tropical climate characterized by warm temperatures and seasonal rainfall. Monthly average temperatures range from 25°C (77°F) in January to 27°C (81°F) from June to October, with maxima often reaching up to 29°C (84°F) in the peak of summer. Precipitation is highest from July to October, with October receiving around 122 mm (4.8 in) of rain, while the driest months are January to March, each averaging about 35 mm (1.4 in). The region enjoys considerable sunshine, peaking at 359 hours in May and seeing over 300 hours in most months. For more detailed information, visit Portsmouth climate.
In conclusion, Saint John, Dominica, presents a distinctive tropical climate characterized by consistent warmth, abundant sunshine, and significant UV exposure throughout the year. With a steady increase in temperatures and rainfall during the summer months, the region thrives under its lush, vibrant ecosystem. The consistent daylight hours facilitate outdoor endeavors, while the high UV Index underscores the need for sun protection. Together, these climatic features create an inviting atmosphere for both residents and visitors, offering a rich tropical experience that showcases the natural beauty and biodiversity of this enchanting Caribbean locale.