September Weather in Islamorada, United States

Last updated: February 24, 2025

September in Islamorada, United States, showcases a warm tropical climate characterized by maximum temperatures reaching 30°C (87°F) and an average of 28°C (83°F). The month experiences a minimum temperature of 25°C (77°F), offering comfortable evenings by the coast. However, it also brings significant rainfall, with a total precipitation of 204 mm (8.0 in) over 18 days, leading to a humidity level of 76% that can feel quite muggy. While the weather might challenge outdoor plans, it adds to the lush beauty of this island paradise, making September a unique time to experience Islamorada's vibrant atmosphere.

September Temperature in Islamorada

September in Islamorada offers a warm tropical escape, with temperatures typically ranging from a minimum of 25°C (77°F) to a maximum of 30°C (87°F). The average temperature hovers around 28°C (83°F), making it one of the balmiest months of the year. As summer transitions to fall, these temperatures reflect a consistent warmth that invites outdoor activities, from lounging on sun-soaked beaches to exploring the vibrant marine life. This month maintains the high humidity characteristic of the season, yet the inviting warmth ensures that the stunning sunsets and gentle ocean breezes remain an irresistible allure.

September Weather in Islamorada: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Islamorada, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec717373777982838382817673
Data source: Temperature data for Islamorada generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Islamorada

In September, Islamorada experiences a significant surge in precipitation, with 204 mm (8.0 in) of rainfall spread over 18 days. This marks a notable increase compared to the previous months, highlighting September as one of the wettest times of the year. Following the warmer summer months, where rainfall ranged between 113 mm (4.4 in) and 157 mm (6.2 in), the arrival of September's intense downpours signals a shift in weather patterns, as tropical systems can influence the region. This uptick not only showcases the tropical climate's variability but also sets the stage for the transition into the drier months ahead, offering a brief, yet vibrant, contrast to the more moderate conditions of October and November.

September Precipitation Trends in Islamorada

The chart displays monthly precipitation patterns in Islamorada, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec243223501571251131172041367142
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Islamorada

In September, Islamorada experiences a humidity level of 76%, marking a slight increase from the summer months of June (69%) and July (70%). This rise reflects a typical shift as the region transitions from the drier months of late spring into the more humid conditions of early fall. Although humidity levels do drop slightly from August's 72%, the approaching autumn still brings moisture that contributes to the lush tropical atmosphere of the Florida Keys. As the year progresses, humidity levels gradually climb back to 79% in October, suggesting that the higher humidity is a seasonal characteristic that envelops the area, adding to its enchanting weather patterns throughout the year.

September Average Humidity in Islamorada

This chart illustrates the average monthly humidity levels in Islamorada, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec81%80%76%73%71%70%70%72%76%79%80%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Islamorada

As September rolls in, the UV Index in Islamorada remains notably high at 12, keeping it in the extreme exposure category. This means that sun protection is crucial, with a burn time of just 10 minutes for unprotected skin. Interestingly, this index mirrors the peak levels seen in the summer months of June, July, and August, highlighting a trend of persistent solar intensity in the region. Travelers and locals alike should stay vigilant about sun safety, as these extreme levels demand actionable precautions. For more detailed information on UV exposure trends, check out the Islamorada UV Index.

Maximum UV Index Levels in Islamorada for September

The chart shows the monthly maximum UV Index (UVI) for Islamorada in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec69101212131212121086
Data source: Islamorada September UVI data generated using information from the Copernicus Climate Change Service.

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.

September Sunshine in Islamorada

September in Islamorada boasts an impressive 313 hours of sunshine, continuing the trend of radiant summer days that began in July, which recorded the highest at 341 hours. As the summer heat gradually winds down, this month still offers ample sunshine, only slightly dipping from August’s 334 hours. This vibrant glow in September paves the way for a sunny transition into autumn, with October forecasted to enjoy 304 hours of sunlight. With the sun casting its warm embrace, September stands as a beautiful blend of lingering summer vibes and the gentle shift towards cooler days, making it an ideal time for outdoor adventures and seaside relaxation.

Monthly Sunshine Duration in Islamorada: September Highlighted

The September sunshine duration represents the total number of hours Islamorada experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec230h283h328h338h330h311h341h334h313h304h281h290h
Data source: Islamorada September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Islamorada During September

In Islamorada, September sees a 33% chance of sunny weather, marking a notable dip compared to the sun-soaked months earlier in the year. After experiencing peak sunshine in the winter and early spring, the summer months bring a significant decline, with June, July, and August each hovering below 30%. This trend indicates that by September, visitors may encounter more overcast skies and rain. Interestingly, the chance of sunnier days improves again in October, climbing back to 50%. So, while September might not be the sunniest month on the calendar, it serves as a transition towards more favorable weather as the year winds down.

Percentage of Sunny Days in September in Islamorada

The chart illustrates the percentage of sunny days in Islamorada throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Islamorada experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec44%67%67%59%57%17%25%26%33%50%50%70%
Data source: Islamorada September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Islamorada in September

As summer fades into autumn, September in Islamorada offers a balanced 12 hours of daylight, reflecting a gradual transition from the longer days of summer. Starting from January's shorter 10-hour days, the daylight duration steadily increased until peaking in May, June, and July with 13 hours of sunlight. August sees a slight dip, but September marks a stabilizing return to 12 hours, embodying the sense of equilibrium before the days shorten again in October. This rhythmic cycle not only influences the beauty of the landscape but also invites locals and visitors alike to enjoy the enchanting evenings that follow the sun's descent.

Average Daylight Hours in Islamorada for September

The chart illustrates the variation in daylight duration in Islamorada throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 46m11h 18m12h 1m12h 44m13h 21m13h 38m13h 29m12h 57m12h 15m11h 32m10h 54m10h 36m
Data source: Islamorada daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Islamorada

As September rolls into Islamorada, the winds noticeably soften, marking a distinct transition as average wind speeds dip to 3.3 m/s (7 mph). This gentle breeze contrasts sharply with the more robust winds of earlier months, where March and April boasted averages of 6.3 m/s (14 mph) and 5.7 m/s (13 mph), respectively. Following the summer peak, the waning winds signal a quieter time in this coastal paradise, inviting serene afternoons and tranquil evenings. As the year progresses towards October, a slight uptick in wind speed to 5.0 m/s (11 mph) suggests a gradual return to the more lively breezes typical of the fall season, underscoring the dynamic climate of this beautiful locale.

Average September Wind Speed in Islamorada

The chart displays monthly wind speed patterns in Islamorada, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec4.86.16.35.75.75.44.25.03.3 m/s5.05.34.5
Data source: Islamorada September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Islamorada Compares to Other Months

The weather in Islamorada changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Islamorada and find detailed weather information for every month.

September and January present stark contrasts in weather conditions. In September, temperatures are notably higher, with a minimum of 25°C (77°F) and an average of 28°C (83°F), peaking at 30°C (87°F). This month is also characterized by significant rainfall, receiving 204 mm (8.0 in) over 18 days, contributing to a humidity level of 76%. In contrast, January is much cooler, with temperatures ranging from a minimum of 10°C (50°F) to an average of 21°C (71°F) and a maximum of 26°C (79°F). The precipitation is minimal in January, totaling only 24 mm (0.9 in) over 4 days, and the humidity slightly increases to 81%. For a more detailed look at January's weather, you can visit Islamorada weather in January.

September and February present distinct weather contrasts. September boasts higher temperatures, with a minimum of 25°C (77°F) and an average of 28°C (83°F), peaking at 30°C (87°F). It also experiences significant rainfall, with 204 mm (8.0 in) over 18 days and a humidity level of 76%. In contrast, February features more temperate conditions, with a minimum temperature of 14°C (58°F) and an average of 23°C (74°F), reaching a maximum of 26°C (79°F). Precipitation drops dramatically to 32 mm (1.3 in) across 7 days, and the humidity is slightly higher at 79%. For more details on this month’s climate, check out Islamorada weather in February.

In September, the weather is notably warmer with average temperatures around 28°C (83°F), peaking at a maximum of 30°C (87°F), while nighttime lows hover at 25°C (77°F). This month also brings considerable rainfall, with 204 mm (8.0 in) of precipitation over 18 days, contributing to a consistently high humidity level of 76%.

In contrast, March experiences milder temperatures, with an average of 23°C (74°F) and maximums of 26°C (80°F). The month is characterized by significantly less rainfall, averaging only 23 mm (0.9 in) across just 3 days, while maintaining the same humidity level of 76%.

For more details on March weather in this region, visit Islamorada weather in March.

In comparing the weather between September and April, September tends to be significantly warmer, with average temperatures around 28°C (83°F) and highs reaching up to 30°C (87°F). In contrast, April offers cooler temperatures, with a minimum of 17°C (63°F) and an average of 25°C (77°F). Moreover, September is much wetter, receiving 204 mm (8.0 in) of precipitation over 18 days, while April sees only 50 mm (2.0 in) over 9 days, leading to drier conditions in the latter month. Humidity levels are also slightly higher in September at 76%, compared to 73% in April. For more detailed insights, check out Islamorada weather in April.

In comparing the weather between September and May, September tends to be warmer and wetter. With average temperatures reaching 28°C (83°F) and maximums of 30°C (87°F), it is slightly hotter than May, which has an average of 26°C (79°F) and a maximum of 29°C (84°F). Additionally, September experiences significantly more precipitation, with 204 mm (8.0 in) falling over 18 days, compared to May's 157 mm (6.2 in) over just 13 days. The humidity in September is also higher at 76%, compared to 71% in May, adding to the overall muggy feel of the month. For those interested in more specific details about the weather in May, you can check Islamorada weather in May.

When comparing the weather in September and June, both months feature similar average temperatures, hovering around 28°C (82°F). However, September tends to be slightly warmer, with a maximum temperature of 30°C (87°F) compared to June's peak of 31°C (88°F). The most notable difference lies in the precipitation levels, as September experiences significantly higher rainfall, totaling 204 mm (8.0 in) over 18 days, whereas June sees just 125 mm (4.9 in) across the same number of days. Additionally, September is more humid, with a humidity level of 76%, compared to June's 69%. For a closer look at the weather conditions, you can check Islamorada weather in June.

In comparing the weather between September and July, we find some intriguing similarities and differences. Both months feature a minimum temperature of around 25°C (77°F) and an average of 28°C (83°F), but July slightly edges out September with a maximum temperature of 31°C (87°F) compared to September's 30°C (87°F). While July experiences less rainfall, with 113 mm (4.4 in) over 18 days, September sees a significant increase in precipitation, totaling 204 mm (8.0 in) also over 18 days. Additionally, September's humidity level of 76% surpasses July's 70%, contributing to a more humid atmosphere. For a deeper look into July's climate specifics, you can check Islamorada weather in July.

In comparing the weather of September to August, September experiences a similar range of temperatures, with minimums around 25°C (77°F) and maximums reaching 30°C (87°F) in both months. However, September is slightly cooler on average at 28°C (83°F), contrasted with August's higher average of 29°C (84°F). Notably, September sees a significant increase in precipitation, with 204 mm (8.0 in) over 18 days, compared to August's 117 mm (4.6 in) during the same number of days. The humidity also rises to 76% in September, surpassing August's 72%. For more details on August weather specifically, visit Islamorada weather in August.

In September, the weather tends to be warmer with average temperatures reaching 28°C (83°F) and a minimum of 25°C (77°F). The month experiences substantial rainfall, totaling 204 mm (8.0 in) across 18 days, leading to a high humidity level of 76%. In contrast, October sees a dip in minimum temperatures to 18°C (65°F) while maintaining a similar maximum temperature of 30°C (86°F). Precipitation decreases significantly to 136 mm (5.3 in), occurring over 17 days, and humidity slightly rises to 79%. For more details, check out Islamorada weather in October.

September and November exhibit distinct differences in weather patterns. September boasts warmer temperatures, with a minimum of 25°C (77°F) and an average around 28°C (83°F), peaking at 30°C (87°F). It is also marked by heavy rainfall, accumulating 204 mm (8.0 in) over 18 days, coupled with a humidity level of 76%. In contrast, November sees a cooler climate, with temperatures dipping to a minimum of 15°C (60°F) and averaging 25°C (76°F), peaking at 28°C (83°F). The month is significantly drier, receiving only 71 mm (2.8 in) of precipitation over 10 days, while humidity rises slightly to 80%. For more detailed insights about November weather, you can explore Islamorada weather in November.

In September, the weather is characterized by higher temperatures, with minimums around 25°C (77°F) and averages peaking at 28°C (83°F). This month also experiences considerable rainfall, averaging 204 mm (8.0 in) over 18 days, contributing to a humid atmosphere with 76% humidity. In contrast, December brings cooler temperatures, with a minimum of 13°C (56°F) and an average of 23°C (73°F). Precipitation drops significantly to 42 mm (1.7 in) over just 6 days, although humidity remains relatively high at 81%. For a detailed look at the December climate in Islamorada, visit Islamorada weather in December.

Compare Islamorada's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Islamorada

In September, Islamorada experiences a blend of warm temperatures and elevated humidity, setting it apart from the drier months of the year. With an average temperature hovering around 28°C (83°F), you can expect a balmy atmosphere, often punctuated by afternoon rain. This month typically sees a significant amount of precipitation, making it one of the wetter times in the region. Despite the increased rainfall, September's lush landscapes and vibrant sunsets offer a captivating experience for visitors. To discover more about what to expect throughout the year, check out the full details on Islamorada Climate.