September weather forecast
Chiang Rai, Thailand

Transitioning from August, September in Chiang Rai sees a decline in rainfall rates to 284mm (11.18"). The month ushers in a decrease in daylight hours, giving way to soothing and calm evenings. Equally matched by less humidity and rather mild temperatures, the pleasant weather makes outdoor pursuits enjoyable. As the city inches towards the end of the rain season, the landscapes radiates rejuvenated beauty. September can be enchanting for nature lovers.

Temperature

Chiang Rai marks the start of September with an average high-temperature of a still hot 31.1°C (88°F), hinting at a slight fluctuation from August's 30.9°C (87.6°F). Throughout the nights in September, an average low-temperature of 22.7°C (72.9°F) is noted.

Heat index

September's heat index is appraised at a scorching 42°C (107.6°F). Extra safeguards are necessary to prevent heat exhaustion and heat cramps. Prolonged activity might cause heatstroke.
Factoring in the heat index, values are geared towards shaded areas with light breezes. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', combines both the air temperature and the humidity level to give a perceived human temperature. A person's impression of weather can be shaped by many aspects, among them metabolic variations, pregnancy, and levels of physical activity. It is noteworthy to mention that direct sunlight exposure can augment the felt temperature, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Kids generally face higher risks than adults as they sweat less. Along with their large skin surface compared to their small bodies and higher heat production due to their activities, their vulnerability is increased.
Perspiration and the resultant sweat evaporation are the body's natural thermostat, helping regulate temperature. With excessive moisture in the atmosphere, the effectiveness of the evaporation process is decreased, causing the body to cool down less efficiently, leading to a sensation of overheating. Overheating can ensue when the body accumulates more heat than it can release, and dehydration severity may vary.

Humidity

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

Rainfall

In September, the rain falls for 18 days. Throughout September, 284mm (11.18") of precipitation is accumulated. Throughout the year, there are 137 rainfall days, and 1691mm (66.57") of precipitation is accumulated.

Daylight

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, sunrise is at 06:11 and sunset at 18:09 +07.

Sunshine

In Chiang Rai, the average sunshine in September is 6h.

UV index

March through September, with an average maximum UV index of 12, are months with the highest UV index. 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 UV index of 12 in September translates into these instructions:
Take every essential safety procedure. Individuals with fair skin could sustain burns in less than 5 minutes. The Sun's UV radiation is most potent between 10 a.m. and 4 p.m. Try to limit direct exposure to the Sun during this period. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Every two hours, apply and reapply an SPF 30+ broad-spectrum sunscreen, especially after swimming or engaging in outdoor activities.