September Weather in Si Chiang Mai, Thailand

Last updated: August 27, 2025

In September, the average temperature in Si Chiang Mai, Thailand is a warm 28°C (83°F), with the minimum dipping to 23°C (73°F) and the maximum soaring to 37°C (98°F). You'll also experience significant precipitation with approximately 265 mm (10.4 in) spread over 24 days, leading to a high average humidity of 86%. Be prepared for a tropical experience!

September Temperature in Si Chiang Mai

In September in Si Chiang Mai, the average temperature is 28°C (83°F), with maximums reaching up to 37°C (98°F) and minimums dropping as low as 23°C (73°F). This makes it an ideal time for travelers looking to enjoy warm weather and outdoor activities.

September Weather in Si Chiang Mai: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Si Chiang Mai, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Si Chiang Mai, September typically has an average temperature of 28°C (83°F), with highs reaching up to 37°C (98°F) and lows dropping to around 23°C (73°F).

Data source: Temperature data for Si Chiang Mai generated using information from the Copernicus Climate Change Service.

September Precipitation in Si Chiang Mai

In Si Chiang Mai in September, the total precipitation amount reaches 265 mm (10.4 in), occurring over the span of 24 days.

September Precipitation Trends in Si Chiang Mai

The chart displays monthly precipitation patterns in Si Chiang Mai, 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 Si Chiang Mai, September typically receives around 265 mm (10.4 inches) of precipitation spread over approximately 24 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Si Chiang Mai

In Si Chiang Mai in September humidity is 86%. With an average temperature of 28°C (83°F), this humidity feels like a heavy blanket enveloping you, making every step feel sluggish and every breath a reminder of the tropical heat, which can be quite challenging for traveling.

September Average Humidity in Si Chiang Mai

This chart illustrates the average monthly humidity levels in Si Chiang Mai, 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 Si Chiang Mai is approximately 86%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Si Chiang Mai

In Si Chiang Mai in September, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in Si Chiang Mai, you can check here.

Maximum UV Index Levels in Si Chiang Mai for September

The chart shows the monthly maximum UV Index (UVI) for Si Chiang Mai 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 Si Chiang Mai typically reaches 14, which falls under the extreme exposure category.

Data source: Si Chiang Mai 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.

How September Weather in Si Chiang Mai Compares to Other Months

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

This table compares monthly weather conditions in Si Chiang Mai, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	24°C (75°F)	6 mm (0.2 inches)	52%	very high
February Weather	25°C (76°F)	17 mm (0.7 inches)	49%	extreme
March Weather	28°C (82°F)	41 mm (1.6 inches)	39%	extreme
April Weather	29°C (85°F)	70 mm (2.8 inches)	40%	extreme
May Weather	29°C (85°F)	204 mm (8.0 inches)	69%	extreme
June Weather	29°C (85°F)	309 mm (12.2 inches)	81%	extreme
July Weather	29°C (84°F)	331 mm (13.0 inches)	83%	extreme
August Weather	28°C (83°F)	402 mm (15.8 inches)	87%	extreme
September Weather	28°C (83°F)	265 mm (10.4 inches)	86%	extreme
October Weather	28°C (82°F)	129 mm (5.1 inches)	74%	extreme
November Weather	26°C (79°F)	10 mm (0.4 inches)	63%	very high
December Weather	23°C (74°F)	7 mm (0.3 inches)	57%	very high