September Weather in Kathmandu, Nepal

Last updated: August 31, 2025

In September, Kathmandu experiences a warm and humid climate, with average temperatures hovering around 22°C (71°F), peaking at a maximum of 29°C (84°F) and dipping to a minimum of 17°C (62°F). The month is marked by significant rainfall, accumulating about 408 mm (16.1 in) over 29 days, making it a particularly wet period for the city. With humidity levels soaring to 92%, the air often feels heavy, shaping the daily experience and inviting residents and visitors alike to embrace the lush greenery that follows the downpours.

September Temperature in Kathmandu

In September, Kathmandu experiences a pleasant transition as summer gently gives way to autumn. With temperatures ranging from a minimum of 17°C (62°F) to a maximum of 29°C (84°F), the month strikes a perfect balance, allowing for comfortable outdoor explorations. The average temperature hovers around 22°C (71°F), offering a delightful respite from the humid summer months. As the rainfall starts to ease, clear skies often grace the city, inviting both locals and tourists to savor the vibrant scenery and rich cultural heritage. The gradual cooling trend offers a refreshing backdrop as the region prepares for the cooler months ahead, making September an ideal time to visit this enchanting Himalayan city.

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

The chart illustrates September temperature patterns in Kathmandu, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Kathmandu, 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).
JanFebMarAprMayJunJulAugSepOctNovDec495360656872727271665852
Data source: Temperature data for Kathmandu generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Kathmandu

In September, Kathmandu experiences a notable transition as the monsoon begins to wane, bringing 408 mm (16.1 in) of precipitation over 29 days. This significant rainfall, while lighter than the peak of the monsoon in July and August, still plays a crucial role in replenishing the region's water resources. The city's weather during this month is characterized by a gradual decrease in intensity, marking a shift towards drier conditions that will persist into the autumn months. The contrast to the heavier downpours of summer, with September's rainfall representing about 39% of the total average rainfall from June to August, illustrates a promising reduction in the relentless monsoon while still keeping the lush landscape vibrant and alive.

September Precipitation Trends in Kathmandu

The chart displays monthly precipitation patterns in Kathmandu, 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 Kathmandu, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec51566711426552310377844081161929
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Kathmandu

In September, Kathmandu experiences consistently high humidity levels, maintaining a significant 92%, which mirrors the peak humid months of July and August. This trend highlights the city's transition into autumn, where the monsoon season still lingers, resulting in a thick, moisture-laden atmosphere. Prior to September, the humidity steadily climbs from a low of 25% in April, indicating a shift from the drier months towards an increasingly damp climate. As the year progresses, humidity begins to taper off in October to 87%, but September stands out as a peak of discomfort, enveloping the city in a warm, humid blanket that profoundly impacts both the local environment and the daily lives of residents.

September Average Humidity in Kathmandu

This chart illustrates the average monthly humidity levels in Kathmandu, 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 Kathmandu is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec58%53%32%25%46%77%92%92%92%87%76%71%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Kathmandu

In September, Kathmandu experiences a UV Index of 12, categorizing it within the extreme exposure level, which means an average burn time of just 10 minutes. Following the intense UV levels of the summer months, September continues to reflect a trend of elevated UV radiation, though slightly lower than July's peak of 14. This high UV exposure serves as a reminder for residents and visitors alike to take precautionary measures, such as using sunscreen and wearing protective clothing. As the monsoon recedes and the days continue to shorten, it’s a good time to stay informed about safety guidelines related to UV exposure. For more detailed insights, you can check out the Kathmandu UV Index.

Maximum UV Index Levels in Kathmandu for September

The chart shows the monthly maximum UV Index (UVI) for Kathmandu 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 Kathmandu typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec5791111131413121075
Data source: Kathmandu 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 Kathmandu

September in Kathmandu reveals a radiant transition from the intense summer sunshine to the cooler autumn days, boasting an impressive 267 hours of sunlight. This month marks a slight dip compared to the sun-soaked days of May and April, yet it still offers plenty of warmth and brightness after the monsoon deluges of July and August. As daylight begins to wane, the gradual decrease in sunlight hours hints at the approaching winter, yet September fosters a lingering sense of vitality, bridging the vibrant energy of summer with the tranquil beauty of fall. The city's charm is truly magnified under the golden rays, making it an ideal time for exploration and adventure.

Monthly Sunshine Duration in Kathmandu: September Highlighted

The September sunshine duration represents the total number of hours Kathmandu 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.
JanFebMarAprMayJunJulAugSepOctNovDec241h281h336h340h349h314h227h246h267h315h290h289h
Data source: Kathmandu September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Kathmandu During September

In Kathmandu, Nepal, the likelihood of sunny weather sees a notable decline during the monsoon months, with September experiencing only a 14% chance of sunshine. Following the vibrant spring months, which boast probabilities as high as 71% in April, cloud cover and rainfall begin to dominate the landscape as summer and early autumn arrive. The weather starts shifting dramatically in May and continues its descent, dipping to a mere 2% sunny days by August. As September arrives, the chances of encountering sun-filled skies are slim, marking it as one of the less favorable months for sunshine seekers. However, as the monsoon recedes, prospects improve again heading into October, where the chance of clear skies rises to 41%, signaling a gradual return to Kathmandu's sunny disposition.

Percentage of Sunny Days in September in Kathmandu

The chart illustrates the percentage of sunny days in Kathmandu 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 Kathmandu experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec55%67%69%71%28%18%4%2%14%41%47%60%
Data source: Kathmandu September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Kathmandu in September

As September arrives in Kathmandu, daylight begins to taper off, offering 12 hours of sunlight—a gentle transition from the summer months of longer days. After experiencing a peak of 13 hours in the preceding summer, the gradual decrease reflects the natural rhythm of the changing seasons. This month stands as a bridge, cradled between the lush, sunlit days of July and August, and the shorter, cooler days that will follow in October. The daylight duration hints at the approaching autumn, making September a beautiful time to soak in the still generous hours of sunlight before the year slowly retreats into the darker months ahead.

Average Daylight Hours in Kathmandu for September

The chart illustrates the variation in daylight duration in Kathmandu throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 35m11h 12m12h12h 49m13h 30m13h 51m13h 40m13h 4m12h 17m11h 28m10h 46m10h 24m
Data source: Kathmandu daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Kathmandu

In September, the gentle breezes of Kathmandu average a modest 0.8 m/s (2 mph), signaling the transition towards autumn. This marks the lowest wind speed of the year, following a summer where winds barely stirred, staying at 0.9 m/s (2 mph) in both July and August. As the monsoon clouds recede, the air becomes still, creating a serene atmosphere ideal for reflecting on the beauty of the city’s heritage. Leading into October, where winds slightly increase again to 1.0 m/s (2 mph), one can sense the calm that September offers, inviting residents and visitors alike to bask in the tranquil sights of the evolving landscape. Thus, September stands out as a month of peaceful quietude, preparing the way for the more dynamic autumn winds to come.

Average September Wind Speed in Kathmandu

The chart displays monthly wind speed patterns in Kathmandu, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1.21.11.41.61.01.10.90.90.8 m/s1.01.11.1
Data source: Kathmandu September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Kathmandu Compares to Other Months

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

September and January present a striking contrast in weather, highlighting the shift from the warmth of late summer to the chill of winter. In September, temperatures range from a mild 17°C (62°F) to a warm 29°C (84°F), with an average of 22°C (71°F). This month is also characterized by significant rainfall, with 408 mm (16.1 in) of precipitation spread over 29 days and high humidity at 92%. In contrast, January experiences much cooler temperatures, with a minimum of 0°C (32°F) and a maximum of 22°C (72°F), averaging just 9°C (49°F). The precipitation drops dramatically to 51 mm (2.0 in), occurring on only 6 days, and humidity decreases to a more comfortable 58%. This clear difference underscores the distinct seasonal changes in Kathmandu's climate. For a deeper dive into January weather specifics, check out Kathmandu weather in January.

The weather in September and February contrasts significantly, reflecting the transition from late summer to early spring. In September, temperatures range from a minimum of 17°C (62°F) to a maximum of 29°C (84°F), with an average of 22°C (71°F). The month is quite rainy, with a total precipitation of 408 mm (16.1 in) spread over 29 days, resulting in high humidity levels of 92%. In stark contrast, February features a cooler climate, with temperatures ranging from a minimum of 2°C (35°F) to a maximum of 23°C (73°F), averaging just 12°C (53°F). Additionally, February is much drier, receiving only 56 mm (2.2 in) of precipitation over 9 days and experiencing lower humidity at 53%. For a more detailed look at February's weather, visit Kathmandu weather in February.

September and March showcase distinct contrasts in weather conditions. September is characterized by warmer temperatures, with a minimum of 17°C (62°F) and an average of 22°C (71°F), reaching up to a maximum of 29°C (84°F). This month also experiences high humidity at 92% and significant precipitation, totaling 408 mm (16.1 in) over 29 days. In contrast, March sees much cooler temperatures, with a minimum of 2°C (36°F) and an average of 16°C (61°F), peaking at 27°C (81°F). The precipitation in March is significantly lower at 67 mm (2.6 in) over just 12 days, and the humidity drops to 32%. For a detailed look at the weather in Kathmandu during March, visit Kathmandu weather in March.

September and April present quite contrasting weather patterns. In September, temperatures range from a mild minimum of 17°C (62°F) to a warm maximum of 29°C (84°F), but the month is characterized by high humidity levels at 92% and considerable rainfall, totaling 408 mm (16.1 in) over 29 days. In contrast, April features cooler conditions with temperatures ranging from a low of 8°C (46°F) to a pleasant average of 19°C (66°F), and similar maximums of 29°C (84°F). April sees significantly less precipitation, only 114 mm (4.5 in) over 17 days, accompanied by much lower humidity at 25%. For a more detailed look at April weather, you can check out Kathmandu weather in April.

September and May in Kathmandu offer notably different weather experiences. September tends to be warmer, with average temperatures around 22°C (71°F) and highs reaching up to 29°C (84°F). However, it also brings significant rainfall, averaging 408 mm (16.1 in) over 29 days and a high humidity level of 92%. In contrast, May is slightly cooler, averaging 20°C (68°F) with the same maximum temperature of 29°C (84°F), but it sees less precipitation—about 265 mm (10.4 in) over 25 days—and a much lower humidity of 46%. For a detailed look at the weather conditions in May, you can check out Kathmandu weather in May.

When comparing the weather in September and June, both months experience similar average temperatures ranging from a minimum of 15°C to 17°C and a maximum of 29°C. However, September is slightly warmer on average at 22°C (71°F) compared to June's average of 22°C (72°F). Notably, June sees higher precipitation levels, with 523 mm (20.6 in) compared to September's 408 mm (16.1 in), contributing to June being a wetter month despite having the same number of rainy days at 29. Additionally, June has a lower humidity level of 77% compared to September's notable 92%, making September feel more humid overall. For more details, check out Kathmandu weather in June.

When comparing the weather in September to that of July, we find that both months exhibit similar average temperatures, with September featuring a minimum of 17°C (62°F) and a maximum of 29°C (84°F), while July has a slightly higher minimum temperature of 18°C (65°F). However, July is significantly wetter, with a staggering 1,037 mm (40.8 in) of precipitation over 31 days, compared to September's 408 mm (16.1 in) across 29 days. Both months maintain high humidity levels of 92%, contributing to a muggy atmosphere. For more details, you can visit Kathmandu weather in July.

In comparing the weather between September and August, both months exhibit similar average temperatures, hovering around 22°C (73°F). However, September shows a slight dip in the minimum temperature, with lows averaging 17°C (62°F) compared to August's minimum of 19°C (66°F). While August is characterized by higher maximum temperatures of up to 30°C (86°F), September cools off slightly with a maximum of 29°C (84°F). Precipitation levels are significantly different; September receives 408 mm (16.1 in) over 29 days, whereas August experiences a much wetter climate with 784 mm (30.9 in) over 30 days. Interestingly, both months maintain high humidity levels at 92%. For more detailed insights, check out Kathmandu weather in August.

September and October in Kathmandu showcase a notable shift in weather patterns. In September, temperatures are warmer, with a minimum of 17°C (62°F) and an average of 22°C (71°F), while rainfall is significantly higher at 408 mm (16.1 in) across 29 days, contributing to a humidity level of 92%. By contrast, October sees cooler temperatures, dropping to a minimum of 9°C (48°F) and an average of 19°C (67°F). Precipitation also decreases dramatically to 116 mm (4.5 in) over 16 days, with humidity slightly lowering to 87%. This transition marks a shift towards drier and cooler conditions, making October a more pleasant month overall. For more details, check out Kathmandu weather in October.

September's weather is characterized by warm temperatures, with an average of 22°C (71°F) and daily maximums reaching up to 29°C (84°F). This month is also marked by high precipitation, totaling 408 mm (16.1 in) over 29 days, contributing to a humidity level of 92%. In contrast, November brings a significant drop in temperatures, with averages around 15°C (58°F) and a maximum of 27°C (81°F), while nights can get quite cool, dipping to a minimum of 6°C (42°F). Rainfall is minimal in November, with only 19 mm (0.8 in) recorded over just 6 days and humidity decreasing to 76%. For more detailed information, you can check Kathmandu weather in November.

In September, the weather is warm and humid, with average temperatures ranging from a minimum of 17°C (62°F) to a maximum of 29°C (84°F). The month is characterized by frequent rainfall, with a staggering 408 mm (16.1 in) of precipitation spread over 29 days and humidity levels at a high 92%. In contrast, December experiences much cooler temperatures, with averages between 2°C (35°F) and 22°C (71°F). The precipitation drastically decreases to just 29 mm (1.1 in) over a mere 5 days, and humidity levels drop to 71%. For a more detailed look at December weather, you can visit Kathmandu weather in December.

Compare Kathmandu's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Kathmandu

In September, Kathmandu experiences a distinct shift as the monsoon season reaches its peak, bringing significant rainfall and high humidity levels. While temperatures are pleasantly warm, averaging around 22°C, the prevalence of rainy days can make this month feel quite different from the drier months that follow. With nearly 408 mm of precipitation over 29 days, the lush landscapes flourish, offering a vibrant atmosphere. This blend of warmth and moisture creates a unique backdrop, unlike the more temperate conditions found in October and November. To explore more about what to expect throughout the year, check out the comprehensive details on Kathmandu Climate.