In
September,
Kathmandu witnesses a significant retreat of the monsoons, with rainfall dropping to 200mm (7.87"). The city's aesthetic transforms, presenting a greener and fresher aura, courtesy of the preceding rainfall. While the days continue to be warm, the nights start to cool off, signifying the arrival of autumn. Progressively moving from September to
October, one can see a further decrease in rain and more atmospheric clarity. Consequently, this month is ideal for outdoor activities and sightseeing.
Temperature
The advent of September in Kathmandu observes an average high-temperature of a still moderately hot 28.1°C (82.6°F), nearly identical to
August's 28.7°C (83.7°F). The month of September records an average low-temperature of 18.5°C (65.3°F) in Kathmandu.
Heat index
Throughout September, the heat index is estimated at a tropical 33°C (91.4°F). Adopt extra preventive measures, the occurrence of heat cramps and heat exhaustion is likely. Heatstroke may follow extended activity.
Be informed that the heat index values are oriented around shady conditions and gentle breezes. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'apparent temperature' or 'real feel', melds the effects of warmth and moisture to generate a feeling of heat. Additional factors encompassing metabolic differences, the level of physical activity, and clothing can impact the individual's perception of temperature. Direct sunlight exposure should be noted as it has the potential to increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Kids are usually more vulnerable than adults, given their lesser sweating ability. Along with their larger skin surface relative to their small stature and the excess heat due to their activity, their risk is amplified.
Humidity
The average relative humidity in September in Kathmandu is 82%.
Rainfall
In Kathmandu, in September, during 15 rainfall days, 200mm (7.87") of precipitation is typically accumulated. In Kathmandu, during the entire year, the rain falls for 110 days and collects up to 1455mm (57.28") of precipitation.
Daylight
The average length of the day in September is 12h and 19min.
On the first day of September, sunrise is at 5:42 am and sunset at 6:24 pm. On the last day of the month, sunrise is at 5:56 am and sunset at 5:51 pm +0545.
Sunshine
The months with the least sunshine in Kathmandu are
July and September, with an average of 4.4h of sunshine.
UV index
In September, the average daily maximum UV index in Kathmandu is 11. A UV Index of 11, and more, symbolizes an extreme threat to health from exposure to the Sun's UV rays for ordinary individuals.
Note: The maximum daily UV index of 11 in September interprets into the following recommendations:
Take all necessary precautions, as unprotected skin can burn in minutes. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. For those who get sunburned easily, direct sun exposure should be minimized. Always keep your skin protected with a 30 SPF sunscreen.