September Weather in Heidelberg, South Africa

Last updated: August 31, 2025

In Heidelberg, South Africa, the average temperature in September is a comfortable 18°C (64°F). However, it can swing from a chilly 0°C (32°F) to a warm 33°C (91°F). During this month, you can expect about 9 mm (0.4 in) of precipitation over 2 days, with an average humidity level of 74%.

September Temperature in Heidelberg

In September in Heidelberg, the average temperature is 18°C (64°F). Maximum temperatures can reach 33°C (91°F), while minimums can dip as low as 0°C (32°F). This diverse range of temperatures makes it advisable for travelers to pack layers for varying weather conditions.

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

The chart illustrates September temperature patterns in Heidelberg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Heidelberg, September typically has an average temperature of 18°C (64°F), with highs reaching up to 33°C (91°F) and lows dropping to around 0°C (32°F).

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

September Precipitation in Heidelberg

In Heidelberg in September, the precipitation amount is 9 mm (0.4 in) over the course of 2 days.

September Precipitation Trends in Heidelberg

The chart displays monthly precipitation patterns in Heidelberg, 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 Heidelberg, September typically receives around 9 mm (0.4 inches) of precipitation spread over approximately 2 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 Heidelberg

In Heidelberg in September humidity is 74%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making it ideal for leisurely strolls but potentially uncomfortable for extended outdoor activities.

September Average Humidity in Heidelberg

This chart illustrates the average monthly humidity levels in Heidelberg, 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 Heidelberg is approximately 74%, 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 Heidelberg

In Heidelberg in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Heidelberg.

Maximum UV Index Levels in Heidelberg for September

The chart shows the monthly maximum UV Index (UVI) for Heidelberg 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 Heidelberg typically reaches 11, which falls under the extreme exposure category.

Data source: Heidelberg 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 Heidelberg Compares to Other Months

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

This table compares monthly weather conditions in Heidelberg, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	21°C (69°F)	121 mm (4.8 inches)	79%	extreme
February Weather	20°C (69°F)	126 mm (5.0 inches)	77%	extreme
March Weather	19°C (67°F)	72 mm (2.8 inches)	77%	extreme
April Weather	16°C (62°F)	60 mm (2.4 inches)	81%	very high
May Weather	13°C (56°F)	14 mm (0.5 inches)	82%	high
June Weather	11°C (51°F)	5 mm (0.2 inches)	73%	high
July Weather	10°C (51°F)	2 mm (0.1 inches)	71%	high
August Weather	14°C (57°F)	2 mm (0.1 inches)	68%	very high
September Weather	18°C (64°F)	9 mm (0.4 inches)	74%	extreme
October Weather	19°C (66°F)	66 mm (2.6 inches)	74%	extreme
November Weather	20°C (69°F)	106 mm (4.2 inches)	82%	extreme
December Weather	20°C (69°F)	156 mm (6.1 inches)	81%	extreme