September Weather in Onon, Mongolia

Last updated: August 28, 2025

In Onon, Mongolia, the average temperature in September hovers around 10°C (51°F), with a range that can plunge to a chilly -6°C (21°F) and rise to a warm 29°C (84°F). Expect occasional rain, as 42 mm (1.6 in) of precipitation typically falls over 8 days. Moreover, the atmosphere remains quite humid, with average humidity levels reaching a notable 82%.

September Temperature in Onon

In September in Onon, the average temperature is 10°C (51°F). Maximums can reach 29°C (84°F) and minimums can drop as low as -6°C (21°F). This range makes it essential for travelers to pack layers to accommodate varying weather conditions.

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

The chart illustrates September temperature patterns in Onon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Onon, September typically has an average temperature of 10°C (51°F), with highs reaching up to 29°C (84°F) and lows dropping to around -6°C (21°F).

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

September Precipitation in Onon

In Onon in September, the precipitation amount is 42 mm (1.6 in) over a span of 8 days.

September Precipitation Trends in Onon

The chart displays monthly precipitation patterns in Onon, 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 Onon, September typically receives around 42 mm (1.6 inches) of precipitation spread over approximately 8 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 Onon

In Onon in September humidity is 82%. With an average temperature of 10°C (51°F), this humidity feels like a damp chill that clings to your skin, making outdoor adventures less appealing and prompting travelers to seek cozy indoor activities or warm drinks to counter the brisk air.

September Average Humidity in Onon

This chart illustrates the average monthly humidity levels in Onon, 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 Onon is approximately 82%, 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 Onon

In Onon in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Onon.

Maximum UV Index Levels in Onon for September

The chart shows the monthly maximum UV Index (UVI) for Onon 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 Onon typically reaches 7, which falls under the high exposure category.

Data source: Onon 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 Onon Compares to Other Months

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

This table compares monthly weather conditions in Onon, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-22°C (-7°F)	2 mm (0.1 inches)	92%	low
February Weather	-18°C (0°F)	5 mm (0.2 inches)	86%	moderate
March Weather	-6°C (22°F)	6 mm (0.2 inches)	72%	moderate
April Weather	4°C (39°F)	16 mm (0.6 inches)	67%	high
May Weather	10°C (51°F)	35 mm (1.4 inches)	69%	very high
June Weather	17°C (63°F)	71 mm (2.8 inches)	67%	very high
July Weather	19°C (66°F)	118 mm (4.6 inches)	79%	very high
August Weather	16°C (61°F)	95 mm (3.7 inches)	79%	very high
September Weather	10°C (51°F)	42 mm (1.6 inches)	82%	high
October Weather	0°C (33°F)	20 mm (0.8 inches)	79%	moderate
November Weather	-10°C (14°F)	7 mm (0.3 inches)	81%	moderate
December Weather	-19°C (-2°F)	4 mm (0.1 inches)	90%	low