Last updated: August 21, 2025
Experience the tropical charm of Saint John's, Antigua and Barbuda in September, where the average temperature hovers around 28°C (82°F). With maximums reaching 29°C (85°F) and a comfortable minimum of 25°C (77°F), the climate invites you to bask in the warm sunshine. However, be prepared for the 144 mm (5.7 in) of rainfall, as 21 wet days add a refreshing touch to the bustling atmosphere. Enhanced by an 80% humidity level, the island offers a lush, vibrant environment perfect for adventure and relaxation alike.
In September, temperatures in Saint John's, Antigua and Barbuda continue the trend of warm and inviting conditions typical of the Caribbean. With a minimum temperature of 25°C (77°F) and an average that rises to 28°C (82°F), it's a perfect time to embrace the warm island vibes. The maximum temperature peaks at 29°C (85°F), matching the highs recorded in the preceding summer months of July and August. This slight increase in warmth signals the end of summer, while still maintaining that lovely tropical essence, making September an appealing month for beachgoers and sun-seekers alike. As the warm days drift into cooler nights, the inviting climate encourages outdoor explorations and relaxation under the vibrant skies.
September marks a significant shift in precipitation patterns for Saint John's, Antigua and Barbuda, as it registers the highest monthly rainfall at 144 mm (5.7 in). This dramatic increase can be seen in the context of the broader trend throughout the year, where rainfall begins to escalate notably from July, peaking in September before tapering off again in October. With 21 rainy days, September not only tops the charts for precipitation volume but also presents the longest streak of rainy days in the annual cycle. This highlights the transition into the wet season, setting the stage for the lush landscapes and vibrant ecosystems that characterize the region during this time.
September in Saint John's, Antigua and Barbuda, showcases a notable drop in humidity levels compared to the peak months of July and August, with the humidity settling at a comfortable 80%. This transitional period signals a slight easing from the sticky summer months, which experienced humidity levels reaching as high as 84%. Following a gradual increase from January's 77% to a summer maximum, September's readings indicate a turning point as the air begins to dry slightly, setting the stage for the cooler months ahead. This subtle decline reinforces the characteristic patterns of the Caribbean climate, where humidity is prevalent yet shows a predictable rhythm throughout the year.
September in Saint John's, Antigua and Barbuda continues the trend of intense sun exposure, boasting a UV Index of 13 that falls into the extreme category. With a quick burn time of just 10 minutes, it’s crucial to take sun safety seriously during this month. The UV Index remains consistently high from April through September, highlighting a pattern of extreme sun intensity during the peak travel months. As summer gives way to autumn, taking precautions like applying sunscreen, wearing protective clothing, and seeking shade can help mitigate UV exposure. For more insights on UV levels throughout the year, check the detailed Saint John's UV Index.
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As summer gracefully transitions into autumn, September in Saint John's, Antigua and Barbuda continues to bask in abundant sunshine, offering an impressive 321 hours of daylight. While this marks a decline from the peak sunshine of July, which boasts a vibrant 361 hours, it remains a delightful month for outdoor activities and exploration. The trend of gradually diminishing daylight persists into the fall, with October slightly dropping to 318 hours. Yet, September retains a warm glow, fusing the lingering warmth of summer with the beginnings of a more relaxed season, making it a perfect time for beachgoers and nature enthusiasts alike to enjoy the captivating outdoors.
In September, Saint John's, Antigua and Barbuda, enjoys a 58% chance of sunny weather, making it a delightful month for those seeking basking sunlight after the summer heat. This percentage aligns with the sunny probabilities seen in January, indicating a potential trend of lingering pleasant weather as the year transitions toward its close. The month precedes the more reliably sunny conditions of October and November, which boast even higher chances of sunshine at 55% and 68%, respectively. While September may not be the sunniest month of the year, it certainly offers a favorable chance for sun-seekers to enjoy the island's tropical charm before the year shifts gears.
In Saint John's, Antigua and Barbuda, September marks a seamless transition in daylight duration as the summer's long, sunlit days start to recede. After basking in up to 13 hours of daylight during the peak months of June and July, the island experiences a gentle decline, offering 12 hours of daylight in September, akin to the previous month of August. This trend suggests a slow shift towards the shorter days of autumn, where daylight dips to 11 hours by October. As the year unfolds, residents and visitors alike can enjoy the lingering warmth of summer while beginning to embrace the shifting rhythm of the seasons.
In September, the winds in Saint John's, Antigua and Barbuda begin to calm, with an average speed of 5.2 m/s (12 mph), marking it as one of the most tranquil months of the year. This drop in wind intensity stands out when contrasted with the peak of the earlier months, such as February, which boasts an impressive average of 9.2 m/s (21 mph). Following the vibrant summer breeze, September’s gentler winds gently usher in the transition to fall, creating a serene atmosphere that’s perfect for leisurely exploration of the island's stunning landscapes. As the year progresses, from the lively gusts of July and August to the quieter September, it’s evident that the winds play a significant role in shaping the island's seasonal charm.
Weather in Saint John's varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Saint John's, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather is notably warmer and more humid, with average temperatures reaching 28°C (82°F) and a high of 29°C (85°F). During this month, significant rainfall is common, averaging 144 mm (5.7 in) across 21 days, resulting in an 80% humidity level. In contrast, January offers a slightly cooler climate, with average temperatures at 25°C (78°F) and a maximum of 27°C (80°F). Rainfall is much lower in January, totaling only 34 mm (1.4 in) over 12 days, and humidity drops to 77%. For more details, visit Saint John's weather in January.
September and February present noticeably different weather conditions. In September, temperatures are warmer, with a minimum of 25°C (77°F) and an average of 28°C (82°F), peaking at a maximum of 29°C (85°F). However, it is also more humid at 80%, with significant precipitation of 144 mm (5.7 in) falling over 21 days. In contrast, February is cooler and drier, featuring a minimum temperature of 22°C (72°F) and an average of 25°C (77°F), reaching a maximum of 26°C (80°F). The humidity is slightly lower at 76%, with only 36 mm (1.4 in) of precipitation spread over 14 days. For more detailed weather insights, check out Saint John's weather in February.
September and March exhibit notable differences in weather patterns. September tends to be warmer, with average temperatures around 28°C (82°F) compared to March's cooler average of 25°C (77°F). Additionally, September experiences significantly higher precipitation, with 144 mm (5.7 in) across 21 days, while March sees just 31 mm (1.2 in) over 11 days. Humidity levels are also higher in September at 80%, compared to March's 76%. For more detailed information about the weather in March, you can visit Saint John's weather in March.
In September, the weather is generally warmer with temperatures ranging from a minimum of 25°C (77°F) to a maximum of 29°C (85°F) and an average of 28°C (82°F). This month also experiences a higher level of precipitation, totaling 144 mm (5.7 in) over 21 days, combined with a humidity level of 80%. In contrast, April offers milder temperatures, with a minimum of 23°C (74°F) and a maximum of 27°C (82°F), averaging around 25°C (78°F). Precipitation is significantly less in April, amounting to only 38 mm (1.5 in) over 14 days, and humidity is slightly lower at 78%. For more detailed insights on April weather, you can check Saint John's weather in April.
When comparing the weather in September to that in May, it is clear that September tends to be slightly warmer and wetter. In September, temperatures vary from a minimum of 25°C (77°F) to a maximum of 29°C (85°F), with an average of 28°C (82°F). This month also experiences significant rainfall, totaling 144 mm (5.7 in) over 21 days, leading to high humidity levels at 80%. In contrast, May offers a somewhat milder climate, with temperatures ranging from a minimum of 24°C (75°F) to a maximum of 28°C (82°F) and an average of 26°C (79°F). May sees far less precipitation, at 49 mm (1.9 in) across 15 days, with humidity being slightly lower at 79%. For more detailed insights, check out Saint John's weather in May.
When comparing the weather in September and June, we see subtle differences in temperature and precipitation. September typically experiences slightly higher temperatures, with an average of 28°C (82°F) compared to June's average of 27°C (80°F). However, September is marked by significantly higher precipitation, with 144 mm (5.7 in) over 21 days, while June only sees 52 mm (2.0 in) over 14 days. Humidity levels are quite similar, with September at 80% and June at 81%. Those looking for more information can refer to Saint John's weather in June for a detailed overview of the conditions during that month.
When comparing the weather in September and July, both months experience warm temperatures with minimal variation. September has an average temperature of 28°C (82°F), while July averages slightly cooler at 27°C (81°F). Both months see highs of 29°C (84°F - 85°F). However, September is notably wetter, receiving 144 mm (5.7 in) of precipitation over 21 days compared to July's 81 mm (3.2 in) across 19 days. Humidity is also slightly higher in July at 84%, compared to September's 80%. For more details, you can check Saint John's weather in July.
In comparing the weather of September and August, we observe that both months maintain similar temperature ranges, with September showing a slightly higher average temperature of 28°C (82°F) compared to August's 27°C (82°F). However, September experiences significantly more precipitation, totaling 144 mm (5.7 in) over 21 days, in contrast to August's 97 mm (3.8 in) over 18 days. Additionally, September has a slightly lower humidity level at 80% compared to August's 83%. For detailed information on August weather, you can check Saint John's weather in August.
In comparing the weather of September and October, both months share similar temperature ranges, with minimums at 25°C (77°F) and maximums peaking at 29°C (85°F). However, October sees a slight dip in the average temperature to 27°C (81°F), while also experiencing less precipitation at 109 mm (4.3 in) over 18 days compared to September’s 144 mm (5.7 in) across 21 days. Additionally, humidity levels remain comparable, with October slightly lower at 79% versus September's 80%. For more detailed insights, you can check Saint John's weather in October.
In September, the weather tends to be warmer with average temperatures reaching around 28°C (82°F) and maximums peaking at 29°C (85°F). The month also sees considerable rainfall, with approximately 144 mm (5.7 in) of precipitation spread over 21 days, maintaining a high humidity level of 80%. In contrast, November offers slightly cooler temperatures, with an average of 27°C (80°F) and maximums of 28°C (83°F). Rainfall decreases significantly to 94 mm (3.7 in) over 17 days, while humidity remains constant at 80%. For more detailed information, you can visit Saint John's weather in November.
In comparing the weather between September and December, September tends to be warmer and wetter. The average temperature in September is slightly higher, at 28°C (82°F), compared to December's 26°C (79°F). Additionally, September experiences significant rainfall with 144 mm (5.7 in) over 21 days, whereas December sees much less precipitation at 52 mm (2.1 in) spread over 18 days. Humidity levels are quite similar, with September at 80% and December at 78%. Overall, September is characterized by a more tropical climate, while December offers a slightly cooler and drier experience. For more detailed insights, you can visit Saint John's weather in December.
As September unfolds in Saint John, it brings a noticeable shift in weather patterns compared to the drier and more temperate months that precede it. With higher humidity levels and frequent rainfall, this month becomes one of the wettest times of the year, showcasing its lively atmosphere. The temperatures remain warm, nudging the average close to the highs of summer, but the increased precipitation often leads to a more tropical feel. This combination not only enriches the lush landscapes but also sets a vibrant backdrop, making this time an interesting contrast to the drier, sunnier days of the summer season. For a deeper understanding of what to expect throughout the year, check out Saint John's Climate.