September Weather in Dehiwala-Mount Lavinia, Sri Lanka

Last updated: March 19, 2025

In September, Dehiwala-Mount Lavinia, Sri Lanka, experiences tropical conditions characterized by a maximum temperature of 30°C (86°F) and an average temperature hovering around 27°C (81°F). The weather is marked by significant humidity levels at 82%, contributing to a palpable warmth. This month witnesses considerable rainfall, with 238 mm (9.4 in) spread over 26 days, making it one of the wetter periods of the year. Visitors can expect lush landscapes and vibrant scenery amid intermittent showers, creating a lush tropical environment that is both captivating and refreshing.

September Temperature in Dehiwala-Mount Lavinia

In September, Dehiwala-Mount Lavinia experiences mild tropical conditions, with nighttime temperatures dipping to a comfortable 25°C (77°F). The daytime sees an average warmth of 27°C (81°F), peaking at around 30°C (86°F). This month is characterized by a slight cooling trend compared to the heights of summer, indicating the transition into the autumn months. Overall, the temperatures remain fairly consistent with those of the preceding months, with only minor fluctuations. As September progresses, residents and visitors alike can enjoy the warm yet pleasant climate, making it an ideal time to explore this vibrant coastal region of Sri Lanka.

September Weather in Dehiwala-Mount Lavinia: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Dehiwala-Mount Lavinia, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec818282838382828181818181
Data source: Temperature data for Dehiwala-Mount Lavinia 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 Dehiwala-Mount Lavinia

In September, Dehiwala-Mount Lavinia experiences a significant shift in its precipitation patterns, recording 238 mm (9.4 in) of rainfall over 26 days. This marks a notable increase compared to the preceding months, particularly following the drier spells of July and August. As the region transitions from the peak of the dry season, September’s rains foreshadow the impending surge in precipitation that is typical for October, which hits its peak with 343 mm (13.5 in). The progressive increase in both the volume of rainfall and rainy days reflects the monsoon’s grip tightening, creating a lush, vibrant landscape that thrives on these essential rains. This pattern establishes September as a crucial month for replenishing local ecosystems, setting the stage for the wetter months ahead.

September Precipitation Trends in Dehiwala-Mount Lavinia

The chart displays monthly precipitation patterns in Dehiwala-Mount Lavinia, 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.
JanFebMarAprMayJunJulAugSepOctNovDec5958118133302270188205238343302199
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Dehiwala-Mount Lavinia

September in Dehiwala-Mount Lavinia, Sri Lanka, brings a humidity level of 82%, which is just slightly lower than the peak of 83% observed in August. This marks a continuation of the high humidity trend that characterizes the mid-year months, with humidity levels consistently hovering between 81% and 83% from June through August. As the country transitions into the latter part of the year, September's humidity remains relatively stable, reflecting the tropical climate that defines the region. Following this period, a gradual decline in humidity is expected as the year progresses towards October and November, where levels begin to stabilize around the 80% mark.

September Average Humidity in Dehiwala-Mount Lavinia

This chart illustrates the average monthly humidity levels in Dehiwala-Mount Lavinia, 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.
JanFebMarAprMayJunJulAugSepOctNovDec77%73%74%74%76%82%82%83%82%81%80%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Dehiwala-Mount Lavinia

As September rolls in, Dehiwala-Mount Lavinia continues to experience an extreme UV Index of 14, maintaining the high levels seen throughout the preceding months. This consistency underscores a trend of robust sun exposure, with an unwavering burn time of just 10 minutes—a reminder for residents and visitors alike to take precautions against the sun’s powerful rays. Following a pattern seen since January, the UV Index remains predominantly high, particularly from February through August, peaking at 15 in April before slightly tapering off in October. With these conditions persisting, it’s crucial to stay vigilant and protect your skin. For more detailed information on the UV Index, visit Dehiwala-Mount Lavinia UV Index.

Maximum UV Index Levels in Dehiwala-Mount Lavinia for September

The chart shows the monthly maximum UV Index (UVI) for Dehiwala-Mount Lavinia 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.
JanFebMarAprMayJunJulAugSepOctNovDec121314151412131414131110
Data source: Dehiwala-Mount Lavinia 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 Dehiwala-Mount Lavinia

September in Dehiwala-Mount Lavinia, Sri Lanka, offers a delightful blend of warmth and sunshine, boasting 307 hours of radiant daylight. While this marks a slight dip from the summer peak in March with 336 hours, it remains comfortably above the annual average. As the monsoon season gradually gives way to clearer skies, September’s sun still shines brightly, continuing the trend of consistent sunshine seen throughout the year. From the strong start in January to the gentle decrease towards the end of the year, each month brings its unique charm, making this coastal gem a splendid destination for sunshine seekers.

Monthly Sunshine Duration in Dehiwala-Mount Lavinia: September Highlighted

The September sunshine duration represents the total number of hours Dehiwala-Mount Lavinia 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.
JanFebMarAprMayJunJulAugSepOctNovDec271h310h336h334h314h318h332h327h307h305h283h312h
Data source: Dehiwala-Mount Lavinia September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Dehiwala-Mount Lavinia During September

In September, Dehiwala-Mount Lavinia experiences a modest 19% chance of sunny weather, reflecting a slight decline after the rainy months of August, which sees the lowest likelihood of sunshine at just 9%. This trend of diminishing sunlight continues from the summer months, where higher chances are observed earlier in the year, peaking at 51% in February. As the region transitions towards the end of the monsoon season, September's weather becomes increasingly unpredictable, with a notable uptick in clouds and precipitation. Therefore, while you might find a few sunny days to enjoy coastal activities, it's wise to be prepared for the occasional rain shower as the month unfolds.

Percentage of Sunny Days in September in Dehiwala-Mount Lavinia

The chart illustrates the percentage of sunny days in Dehiwala-Mount Lavinia 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 Dehiwala-Mount Lavinia experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec20%51%32%45%16%22%16%9%19%16%15%54%
Data source: Dehiwala-Mount Lavinia September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Dehiwala-Mount Lavinia in September

As September unfolds in Dehiwala-Mount Lavinia, the region enjoys a steady 12 hours of daylight, continuing the trend established since March. This consistency highlights the tropical climate’s influence, where the daylight duration remains relatively stable throughout the latter half of the year. From January to February, days are slightly shorter at 11 hours, but as spring progresses into the southern summer, the daylight extends, reaching a peak of 12 hours from March through September. As autumn approaches in October, daylight begins to wane again, hinting at the cyclical nature of the region’s illumination. This balance of light and darkness not only shapes daily life but also influences local flora and fauna, creating a harmonious rhythm in this vibrant coastal community.

Average Daylight Hours in Dehiwala-Mount Lavinia for September

The chart illustrates the variation in daylight duration in Dehiwala-Mount Lavinia throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 45m11h 53m12h 4m12h 15m12h 25m12h 29m12h 27m12h 19m12h 8m11h 57m11h 47m11h 43m
Data source: Dehiwala-Mount Lavinia daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Dehiwala-Mount Lavinia

In September, the winds in Dehiwala-Mount Lavinia begin to cool slightly from their summer peak, with an average speed of 5.1 m/s (11 mph). This gentle breeze is a delightful continuation of the stronger winds experienced in the preceding months, particularly in July and August, where speeds reached up to 5.8 m/s (13 mph) and 5.3 m/s (12 mph), respectively. Although September's winds are slightly softer, they still evoke a refreshing energy, hinting at the transition into the more temperate months ahead. With wind speeds gradually tapering off as the year progresses, this month offers a harmonious blend of vitality and serenity—a perfect setting for outdoor activities as the city readies itself for the cooler October days.

Average September Wind Speed in Dehiwala-Mount Lavinia

The chart displays monthly wind speed patterns in Dehiwala-Mount Lavinia, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.24.32.02.94.55.35.85.35.1 m/s4.24.13.2
Data source: Dehiwala-Mount Lavinia September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Dehiwala-Mount Lavinia Compares to Other Months

The weather in Dehiwala-Mount Lavinia 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 Dehiwala-Mount Lavinia and find detailed weather information for every month.

In September, temperatures are typically warm, with a minimum of 25°C (77°F) and a maximum of 30°C (86°F), while the average temperature hovers around 27°C (81°F). September is characterized by high humidity at 82% and considerable rainfall, with 238 mm (9.4 in) of precipitation spread over 26 days. In contrast, January experiences slightly cooler temperatures, with a minimum of 22°C (73°F) and a maximum of 32°C (91°F), yet the average remains the same at 27°C (81°F). January also sees significantly less rainfall, totaling just 59 mm (2.3 in) over 7 days and lower humidity at 77%. For more detailed weather insights, you can visit Dehiwala-Mount Lavinia weather in January.

In September, the weather features generally warmer temperatures with a minimum of 25°C (77°F) and an average of 27°C (81°F), peaking at a maximum of 30°C (86°F). This month is notably wet, receiving 238 mm (9.4 in) of precipitation over 26 days, accompanied by high humidity levels of 82%. In contrast, February presents slightly cooler conditions with a minimum of 23°C (73°F) and an average of 28°C (82°F), reaching up to 33°C (91°F) at times. Significantly less rainfall occurs in February, totaling only 58 mm (2.3 in) across 10 days, with humidity dropping to 73%. For a detailed look at February weather conditions, you can visit Dehiwala-Mount Lavinia weather in February.

In comparing the weather of September and March, both months maintain warm temperatures, with September exhibiting a slightly lower average of 27°C (81°F) compared to March's higher average of 28°C (83°F). The maximum temperatures in March can reach up to 33°C (91°F), making it significantly warmer than September, which caps at 30°C (86°F). However, September experiences a much higher precipitation level at 238 mm (9.4 in) over 26 days, while March sees only 118 mm (4.6 in) across 19 days, resulting in less frequent rain and lower humidity at 74%. For more detailed information on March weather, you can visit Dehiwala-Mount Lavinia weather in March.

When comparing the weather in September and April, it’s evident that both months experience warm temperatures, but April tends to be slightly hotter. In September, the average temperature is around 27°C (81°F), while in April, it rises to about 28°C (83°F). Notably, September has higher humidity at 82%, compared to April's 74%, which can make the warmer temperatures feel more oppressive. Additionally, September sees significantly more rainfall, with 238 mm (9.4 inches) over 26 days, whereas April has only 133 mm (5.3 inches) over 25 days. For a more detailed look at April's climate, check out Dehiwala-Mount Lavinia weather in April.

September and May present contrasting weather patterns despite having similar minimum temperatures. In September, the average temperature is slightly lower at 27°C (81°F) compared to May's 28°C (83°F), with May occasionally reaching a maximum of 32°C (90°F) against September's peak of 30°C (86°F). However, May experiences significantly higher precipitation, totaling 302 mm (11.9 in) over 29 days, while September has 238 mm (9.4 in) across 26 days. Additionally, May's humidity stands at 76%, making it slightly less muggy than September's 82%. For a detailed look at May weather in this region, check out Dehiwala-Mount Lavinia weather in May.

When comparing the weather in September and June, both months exhibit warm temperatures, with minimums around 25°C (77°F) and maximums reaching 30°C (86°F). June tends to be slightly warmer with an average temperature of 28°C (82°F), compared to September’s average of 27°C (81°F). However, September experiences a marginally lower total precipitation of 238 mm (9.4 in) over 26 days, while June has 269 mm (10.6 in) spread over 28 days. Both months share a high humidity level of 82%, which contributes to a muggy atmosphere. For more detailed insights, you can visit Dehiwala-Mount Lavinia weather in June.

Comparing the weather of September and July reveals some notable similarities and differences. Both months experience a minimum temperature of around 25°C (77°F) and maximum temperatures are closely aligned, reaching up to 30°C (86°F) in September and 30°C (87°F) in July. However, September tends to be slightly cooler on average, with an average temperature of 27°C (81°F) compared to July's average of 28°C (82°F). Precipitation levels are higher in September, with 238 mm (9.4 in) of rainfall over 26 days, compared to July's 188 mm (7.4 in) over the same number of days. Interestingly, both months share a high humidity of 82%, contributing to a muggy atmosphere throughout. For more detailed insights, you can check out Dehiwala-Mount Lavinia weather in July.

In comparing the weather of September and August, we see that both months have fairly similar temperature ranges, with September having slightly higher maximum temperatures at 30°C (86°F) compared to August's 29°C (85°F). Both months feature a minimum temperature of 25°C (77°F) and an average temperature of 27°C (81°F). However, September is notably wetter, with a total precipitation of 238 mm (9.4 in) over 26 days, while August recorded 205 mm (8.1 in) over 27 days. Humidity levels are similar, with September at 82% and August slightly higher at 83%. For a more detailed view of August's weather, check out Dehiwala-Mount Lavinia weather in August.

September and October weather shows some similarities as well as differences. Both months share an average temperature of 27°C (81°F), with maximums reaching up to 30°C (86°F). However, September experiences slightly higher minimum temperatures at 25°C (77°F) compared to October's 24°C (76°F). In terms of precipitation, October is noticeably wetter, recording 343 mm (13.5 in) over 29 days, while September had 238 mm (9.4 in) spread across 26 days. Humidity levels are fairly similar, with both months hovering around 81-82%. For more detailed information, you can check out Dehiwala-Mount Lavinia weather in October.

September and November present somewhat similar weather patterns, characterized by warm temperatures and high humidity. In September, the temperatures range from a minimum of 25°C (77°F) to a maximum of 30°C (86°F), with an average of 27°C (81°F), accompanied by considerable rainfall of 238 mm (9.4 in) spread over 26 days and humidity levels at 82%. In contrast, November also maintains an average temperature of 27°C (81°F), but with a slightly higher maximum of 30°C (87°F). However, it experiences an increase in precipitation to 302 mm (11.9 in) over the same number of rainy days, and the humidity decreases slightly to 80%. For more detailed climate insights, you can check out Dehiwala-Mount Lavinia weather in November.

In comparing the weather between September and December, both months share similar average temperatures, hovering around 27°C (81°F). However, September typically experiences slightly warmer conditions with maximum temperatures reaching up to 30°C (86°F) compared to December's peak of 31°C (89°F). Precipitation is notably higher in September, totaling 238 mm (9.4 in) across 26 days, while December sees reduced rainfall of 199 mm (7.8 in) over 18 days. Humidity during both months is quite high, with September at 82% and December at 80%, contributing to a tropical feel throughout the period. For more specific information about the weather conditions in December, you can visit Dehiwala-Mount Lavinia weather in December.

Compare Dehiwala-Mount Lavinia's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Dehiwala-Mount Lavinia

As September unfolds in Dehiwala-Mount Lavinia, it signals a shift in the weather characterized by increased humidity and a notable rise in precipitation. With an average temperature hovering around 27°C, this month stands out for its frequent rain, drenching the region for nearly 26 days, which is significantly higher than in preceding months. The lush greenery thrives under the 82% humidity, creating a vibrant landscape, though the persistent showers might encourage visitors to plan accordingly. While the warmth remains inviting, the rhythmic sound of rain creates a unique atmosphere, making September a truly distinctive month in the coastal charm of Dehiwala-Mount Lavinia. For more insights on weather patterns, explore the detailed Dehiwala-Mount Lavinia Climate.