September weather forecast
Chiang Rai, Thailand

The first month of the autumn, September, is still a hot month in Chiang Rai, Thailand, with an average temperature varying between 22.7°C (72.9°F) and 31.1°C (88°F).

Temperature

In Chiang Rai, Thailand, the average high-temperature in September is essentially the same as in August - a still tropical 31.1°C (88°F). In Chiang Rai, in September, the average low-temperature is 22.7°C (72.9°F).

Heat index

The average heat index in September is estimated at a blistering 42°C (107.6°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'felt air temperature', 'feels like', or 'real feel', combines air temperature and relative humidity to represent a human perceived temperature equivalent. Additional factors like activity, clothing, pregnancy, and metabolic differences affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

In Chiang Rai, the average relative humidity in September is 83%.

Rainfall

In Chiang Rai, it is raining for 18 days, with typically 284mm (11.18") of accumulated precipitation. In Chiang Rai, during the entire year, the rain falls for 137 days and collects up to 1691mm (66.57") of precipitation.

Daylight

In Chiang Rai, the average length of the day in September is 12h and 16min.
On the first day of the month, sunrise is at 06:05 and sunset at 18:36. On the last day of September, in Chiang Rai, Thailand, sunrise is at 06:11 and sunset at 18:10 +07.

Sunshine

In September, the average sunshine is 6h.

UV index

The months with the highest UV index are March through September, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an excessive health risk from exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 12 in September interpret into the following advice:
Practice all-important precautions. Light skin people may get burned in less than 5 minutes. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise.