September Weather in Nairobi, Kenya

Last updated: August 21, 2025

In September, Nairobi experiences a pleasant climate, characterized by a maximum temperature of 28°C (82°F) and a comfortable average of 19°C (66°F). Nighttime brings cooler air, with minimum temperatures dipping to 10°C (50°F). While the month sees some rain, with precipitation amounts reaching 36 mm (1.4 in) over seven days, the humidity remains moderate at 63%, making it an ideal time for outdoor exploration and activities amidst the vibrant urban landscape and stunning natural beauty that Kenya has to offer.

September Temperature in Nairobi

In September, Nairobi experiences a mild and pleasant climate, with temperatures ranging from a minimum of 10°C (50°F) at night to a comfortable maximum of 28°C (82°F) during the day. The average temperature hovers around 19°C (66°F), making it an ideal time for outdoor adventures. As the city transitions from the cooler months of winter, you’ll notice a slight warming trend compared to August’s chill, with temperatures gradually increasing in the lead-up to the hotter months ahead. This perfect blend of cool nights and warm days creates an inviting atmosphere for both visitors and locals, highlighting September as a delightful time to explore the vibrant culture and stunning landscapes of Nairobi.

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

The chart illustrates September temperature patterns in Nairobi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Nairobi, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec686970696765646466686767
Data source: Temperature data for Nairobi 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 Nairobi

September in Nairobi experiences a moderate precipitation level of 36 mm (1.4 in), characteristic of the transition from the dry season to the more rain-laden months ahead. This month sees an average of 7 rainfall days, indicating a slight uptick in moisture compared to the preceding months of July and August, which register lower totals of 21 mm (0.8 in) and 26 mm (1.0 in), respectively. The gradual increase in rainfall sets the stage for October's more substantial deluge of 69 mm (2.7 in), reflecting a shift in the weather pattern as Nairobi heads into its wetter season. This gentle resurgence of rain in September marks a soothing return to the vibrant landscapes that flourish with the onset of the short rains.

September Precipitation Trends in Nairobi

The chart displays monthly precipitation patterns in Nairobi, 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. In Nairobi, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec36338014613355212636699276
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Nairobi

In September, Nairobi experiences a moderate humidity level of 63%, which reflects a slight increase from the drier months preceding it. This trend of rising humidity begins in the latter part of the year, as the city transitions towards October's higher levels of 76%. Following the relative dryness of early months—where humidity dips to 49% in March—September serves as a bridge between the more temperate conditions of winter and the peak humidity witnessed later in the year. The gradual rise is complemented by the approaching rains, typical for this time, indicating a shift that prepares the environment for the lush greenery of the coming months.

September Average Humidity in Nairobi

This chart illustrates the average monthly humidity levels in Nairobi, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Nairobi is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec64%53%49%54%71%70%63%60%63%76%89%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Nairobi

In September, Nairobi experiences a UV Index of 14, classified under the extreme exposure category. This slight drop from the peak summer months shows a continuation of high UV levels that have been consistent since January. Notably, the burn time remains at just 10 minutes, emphasizing the need for diligent sun protection during this time. As the year progresses, Nairobians should remain vigilant; despite the slight fluctuations in the UV Index throughout the months, the potential for skin damage remains significant. To learn more about UV levels throughout the year, check out Nairobi UV Index.

Maximum UV Index Levels in Nairobi for September

The chart shows the monthly maximum UV Index (UVI) for Nairobi 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. In September, the maximum UV index in Nairobi typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec151616161311111314141313
Data source: Nairobi 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 Nairobi

In September, Nairobi basks in a delightful 330 hours of sunshine, continuing a string of bright months that define the region's vibrant climate. Following the warm embrace of August, which recorded a similar amount of sunlight, September maintains this sunny atmosphere, making it a perfect time for outdoor activities and exploring the city's rich culture. As we move into October, an uptick to 343 hours suggests an even sunnier disposition ahead, promising a spectacular transition into the latter part of the year. The consistent availability of sunshine not only embodies Nairobi's charm but also supports its lush landscapes and lively community events, making every day feel like a celebration of warmth and light.

Monthly Sunshine Duration in Nairobi: September Highlighted

The September sunshine duration represents the total number of hours Nairobi 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.
JanFebMarAprMayJunJulAugSepOctNovDec289h313h340h314h336h316h319h330h330h343h330h344h
Data source: Nairobi September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Nairobi During September

In Nairobi, Kenya, September brings a moderate likelihood of sunny weather, with 25% chance of sunshine. This is slightly below the annual average, reflecting a transition from the drier months to the wetter ones. Compared to the preceding months—like August at 29% and October increasing to 34%—September's sunny disposition may feel like a brief, muted reprieve. As the city prepares for the upcoming rainy season, outdoor plans could be met with a mix of clouds and sun, a reminder of Nairobi's dynamic climate as it shifts from one phase to another.

Percentage of Sunny Days in September in Nairobi

The chart illustrates the percentage of sunny days in Nairobi 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 Nairobi experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec46%32%43%26%18%27%11%29%25%34%41%28%
Data source: Nairobi September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Nairobi in September

In Nairobi, Kenya, September ushers in a consistent rhythm of daylight, with the sun gracing the city for a generous 12 hours each day. This remarkable stability in daylight duration is a hallmark of Nairobi's equatorial location, where the passage of the seasons brings little variation in the length of day and night. As the month unfolds, residents and visitors alike can bask in the warm glow of the sun, enjoying vibrant outdoor activities and the city's rich cultural tapestry. Whether it’s a stroll through the lush parks or engaging in local festivities, September's consistent daylight invites a delightful blend of adventure and relaxation.

Average Daylight Hours in Nairobi for September

The chart illustrates the variation in daylight duration in Nairobi throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec12h 9m12h 8m12h 5m12h 4m12h 3m12h 2m12h 2m12h 3m12h 5m12h 7m12h 9m12h 10m
Data source: Nairobi daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Nairobi

In September, Nairobi experiences a gentle breeze, with an average wind speed of 2.4 m/s (5 mph). This month sits comfortably between the calmer months of May and July, which see the lowest winds at 1.8 m/s (4 mph), and the brisker days ahead in October and November, where speeds increase to 2.9 m/s (6 mph) and 3.0 m/s (7 mph) respectively. The trend reveals that while September maintains a moderate wind flow, it hints at the gradual transition toward a more invigorating atmosphere as the year inches closer to its end, creating a delightful balance for residents and visitors alike.

Average September Wind Speed in Nairobi

The chart displays monthly wind speed patterns in Nairobi, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.82.33.52.51.82.01.82.12.4 m/s2.93.03.4
Data source: Nairobi September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Nairobi Compares to Other Months

Weather in Nairobi varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Nairobi, focusing on differences in temperature, rainfall, humidity, and UV levels.

In September, the weather exhibits a mild transition into early autumn, with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 28°C (82°F) and an average of 19°C (66°F). The month experiences about 36 mm (1.4 in) of precipitation over seven days and has a humidity level of 63%. In contrast, January tends to be slightly warmer, with minimum temperatures of 11°C (52°F) and maximums reaching 30°C (86°F), averaging 20°C (68°F). Precipitation remains the same at 36 mm (1.4 in) but occurs over just six days, with humidity at 64%. For more detailed insights, check Nairobi weather in January.

In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 28°C (82°F), with an average of 19°C (66°F). The month experiences 36 mm (1.4 in) of precipitation over 7 days and carries a humidity level of 63%. In contrast, February tends to be slightly warmer, with minimum temperatures around 11°C (53°F) and maximums reaching 31°C (88°F), averaging 21°C (70°F). It sees slightly less precipitation at 33 mm (1.3 in) over the same number of rainy days, but features lower humidity at 53%. For more specific details, you can check Nairobi weather in February.

September and March present contrasting weather patterns. In September, temperatures range from a minimum of 10°C (50°F) to a comfortable maximum of 28°C (82°F), with an average of 19°C (66°F) and relatively mild humidity at 63%. The month sees about 36 mm (1.4 in) of precipitation over roughly 7 days, lending it a drier feel. In contrast, March boasts warmer temperatures, with a minimum of 13°C (55°F) and a peak of 32°C (90°F), averaging 21°C (70°F). However, it experiences significantly more rainfall, totaling 80 mm (3.1 in) over 12 days, and lower humidity at 49%. For more details, check out Nairobi weather in March.

In September, the weather features a mild range of temperatures, with a minimum of 10°C (50°F) and a maximum of 28°C (82°F), resulting in an average of 19°C (66°F). This month has relatively low precipitation at 36 mm (1.4 in) spread over 7 days, accompanied by a humidity level of 63%.

In contrast, April sees warmer conditions with a minimum temperature of 14°C (58°F) and reaching up to 31°C (87°F), giving it an average of 20°C (69°F). However, April is quite wet, experiencing 146 mm (5.7 in) of precipitation over 23 days, and a much lower humidity level of 54%. For more details on April weather in Nairobi, you can view Nairobi weather in April.

In comparing the weather between September and May, both months display similar temperature ranges, with minima around 10-12°C (50-54°F) and maxima reaching up to 28°C (82°F). However, May tends to be wetter, with a substantial increase in precipitation at 133 mm (5.2 in) over 19 days, compared to just 36 mm (1.4 in) over 7 days in September. Additionally, humidity levels are slightly higher in May at 71%, compared to 63% in September, indicating a more humid environment. For those interested in more details, you can find further information about Nairobi weather in May.

In comparing the weather conditions of September and June, both months exhibit relatively mild temperatures, with September enjoying slightly warmer averages. In September, the temperature ranges from a minimum of 10°C (50°F) to a maximum of 28°C (82°F), with an average of 19°C (66°F). In contrast, June has a similar temperature range, with a minimum of 10°C (51°F) and a maximum of 26°C (80°F), averaging 18°C (65°F).

However, June tends to be wetter, with a total precipitation of 55 mm (2.2 in) over about 10 days, compared to September's 36 mm (1.4 in) over 7 days. The humidity is also higher in June at 70%, compared to September's 63%. For more detailed information, you can check the Nairobi weather in June.

In comparing the weather between September and July, both months exhibit similar humidity levels at 63%, creating a comfortable atmosphere. September enjoys slightly warmer temperatures, with an average of 19°C (66°F) compared to July's average of 18°C (64°F). The maximum temperatures also show a marginal increase in September, reaching up to 28°C (82°F) versus July's 27°C (81°F). However, September tends to be wetter, with 36 mm (1.4 in) of precipitation over 7 days, while July experiences less rainfall at 21 mm (0.8 in) across 5 days. For additional details on July weather, you can refer to Nairobi weather in July.

In comparing the weather of September and August, September tends to be slightly warmer, with average temperatures reaching 19°C (66°F) compared to August's 18°C (65°F). The maximum temperature in September also peaks at 28°C (82°F), similar to August's high of 29°C (85°F). While September experiences a bit more precipitation at 36 mm (1.4 in) over 7 days, August records 26 mm (1.0 in) over 6 days, making September the wetter month. Humidity levels are marginally higher in September at 63% compared to August's 60%. For a detailed look at August weather, you can check out Nairobi weather in August.

September and October present a subtle shift in weather conditions. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 28°C (82°F), with an average of 19°C (66°F) and a relatively low humidity of 63%. The month sees about 36 mm (1.4 in) of precipitation over 7 days. In contrast, October brings slightly warmer temperatures, with a minimum of 12°C (54°F) and a maximum of 29°C (85°F), averaging 20°C (68°F). However, it also sees an increase in precipitation to 69 mm (2.7 in) spread over 13 days, leading to a higher humidity of 76%. This makes October feel a bit more humid and wetter compared to the previous month. For more details, check out Nairobi weather in October.

September and November both exhibit mild temperatures, with September averaging 19°C (66°F) and November slightly warmer at 20°C (68°F). While the maximum temperatures are fairly similar, with September reaching 28°C (82°F) and November a touch higher at 29°C (84°F), the two months differ significantly in terms of precipitation. September experiences a moderate rainfall of 36 mm (1.4 in) over about 7 days, whereas November sees a considerable increase, with 92 mm (3.6 in) of rain spread across 16 days. Additionally, humidity levels rise from 63% in September to a more humid 89% in November, contributing to a more tropical feel as the year draws to a close. For more detailed information, check out Nairobi weather in November.

September and December in Nairobi exhibit some similarities, particularly in terms of average temperatures, which remain relatively stable around 19°C (66°F). However, September tends to have slightly lower temperatures, peaking at 28°C (82°F) compared to December's maximum of 28°C (83°F). Precipitation, on the other hand, is significantly higher in December, with 76 mm (3.0 in) recorded over 11 days, compared to September's 36 mm (1.4 in) over just 7 days. Additionally, December experiences higher humidity levels at 84%, compared to September's 63%. For more details, you can refer to Nairobi weather in December.

Compare Nairobi's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Nairobi

As September ushers in the onset of spring in Nairobi, the weather stands out with its mild temperatures and relatively comfortable humidity levels. Unlike the colder months preceding it, September showcases a delightful balance, with pleasant days and refreshingly cool nights. The modest precipitation this month is a gentle reminder of the transitions at play, allowing the city to flourish without overwhelming rain. In comparison to other months, the weather in September is perfect for enjoying outdoor activities and exploring the vibrant surroundings. For a deeper dive into what to expect throughout the year, check out the Nairobi Climate.