September Weather in Bayan, Mongolia

Last updated: August 28, 2025

In September, the average temperature in Bayan, Mongolia is a moderate 13°C (55°F). Nighttime can bring a chill with temperatures dropping to a minimum of -5°C (24°F), while sunny days can soar to a warm 32°C (90°F). With an average humidity of 71%, expect a refreshing atmosphere, though occasional rain may bring 39 mm (1.6 in) of precipitation over about 7 days.

September Temperature in Bayan

In September in Bayan, the average temperature is 13°C (55°F). Maximum temperatures can reach 32°C (90°F), while minimums can drop as low as -5°C (24°F). Be prepared for a wide range of weather conditions when traveling during this time.

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

The chart illustrates September temperature patterns in Bayan, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Bayan, September typically has an average temperature of 13°C (55°F), with highs reaching up to 32°C (90°F) and lows dropping to around -5°C (24°F).

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

September Precipitation in Bayan

In Bayan in September, the precipitation amount is 39 mm (1.6 in) over the course of 7 days.

September Precipitation Trends in Bayan

The chart displays monthly precipitation patterns in Bayan, 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 Bayan, September typically receives around 39 mm (1.6 inches) of precipitation spread over approximately 7 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 Bayan

In Bayan in September humidity is 71%. With an average temperature of 13°C (55°F), this humidity feels like a damp embrace, making travel a bit challenging as the moisture clings to your skin and the air feels thick, creating a sense of heaviness that can sap your energy while exploring.

September Average Humidity in Bayan

This chart illustrates the average monthly humidity levels in Bayan, 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 Bayan is approximately 71%, 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 Bayan

In Bayan in September, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Bayan, you can refer to this Hourly UV Index in Bayan.

Maximum UV Index Levels in Bayan for September

The chart shows the monthly maximum UV Index (UVI) for Bayan 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 Bayan typically reaches 6, which falls under the high exposure category.

Data source: Bayan 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 Bayan Compares to Other Months

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

This table compares monthly weather conditions in Bayan, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-19°C (-3°F)	2 mm (0.1 inches)	91%	low
February Weather	-16°C (3°F)	5 mm (0.2 inches)	82%	moderate
March Weather	-5°C (24°F)	6 mm (0.2 inches)	54%	moderate
April Weather	5°C (41°F)	11 mm (0.4 inches)	53%	high
May Weather	13°C (55°F)	25 mm (1.0 inches)	56%	very high
June Weather	19°C (66°F)	41 mm (1.6 inches)	54%	very high
July Weather	21°C (71°F)	74 mm (2.9 inches)	65%	very high
August Weather	18°C (64°F)	80 mm (3.1 inches)	71%	very high
September Weather	13°C (55°F)	39 mm (1.6 inches)	71%	high
October Weather	2°C (37°F)	21 mm (0.8 inches)	68%	moderate
November Weather	-8°C (17°F)	8 mm (0.3 inches)	65%	low
December Weather	-17°C (2°F)	4 mm (0.1 inches)	81%	low