September weather forecast
Johannesburg, South Africa

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The vast cityscape of Gauteng Province in Johannesburg, South Africa
The vast cityscape of Gauteng Province in Johannesburg, South Africa

Weather in September

September marks the arrival of spring in Johannesburg, bringing noticeable climatic changes. With the rainfall gradually increasing to 27mm (1.06"), September provides relief from the dry conditions of the past months. The temperature too sees a moderate spike, adding to the pleasantness of the season. The city experiences more daylight and sunshine, enhancing the city's outdoor beauty. The UV index jumps back up, corresponding to the increased sunlight.

Temperature

The shift into September in Johannesburg, South Africa, brings a slight increase in the average high-temperature, moving from a refreshing 19.4°C (66.9°F) in August to an agreeable 22.8°C (73°F). Johannesburg reports a marked divergence from daytime peaks throughout September, with lows averaging at a frosty 9.3°C (48.7°F).

Humidity

In Johannesburg, the average relative humidity in September is 47%.

Rainfall

In Johannesburg, in September, it is raining for 3.8 days, with typically 27mm (1.06") of accumulated precipitation. In Johannesburg, during the entire year, the rain falls for 99.3 days and collects up to 713mm (28.07") of precipitation.

Daylight

In September, the average length of the day in Johannesburg is 11h and 57min.
On the first day of the month, sunrise is at 06:19 and sunset at 17:55. On the last day of September, in Johannesburg, sunrise is at 05:47 and sunset at 18:07 SAST.

Sunshine

The month with the most sunshine in Johannesburg is September, with an average of 9.4h of sunshine.

UV index

In Johannesburg, the average daily maximum UV index in September is 9. A UV Index of 8 to 10 symbolizes a very high health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The UV index of 9 during September translates into the following guidance:
Without proper safety measures, skin and eyes can be quickly harmed. Be sure to protect yourself. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
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Frequently asked questions

What is the average September temperature in Johannesburg?

In September, the average high-temperature and low-temperature in Johannesburg, South Africa, are 22.8°C (73°F) and 9.3°C (48.7°F) respectively.

What is the average humidity in September in Johannesburg?

In Johannesburg, the average relative humidity in September is 47%.

How many days does it rain in September in Johannesburg?

In September, in Johannesburg, the rain falls for 3.8 days. Throughout September, 27mm (1.06") of precipitation is accumulated.

How many hours of daylight does Johannesburg have in September?

In Johannesburg, the average day length in September is 11h and 57min.

When are sunrise and sunset in September in Johannesburg?

In September, on the first day of the month, sunrise is at 06:19 and sunset at 17:55. On the last day of the month, in Johannesburg, South Africa, sunrise is at 05:47 and sunset at 18:07 SAST.

What month has the most sunshine in Johannesburg?

September has the most sunshine of the year, with an average of 9.4h of sunshine.

How long on average sun shines in September in Johannesburg?

In Johannesburg, the average sunshine duration in September is 9.4h.

What is the UV index reading in September in Johannesburg?

The average daily maximum UV index in September in Johannesburg is 9. A UV Index value of 8 to 10 symbolizes a very high health vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average UV index

Average temperature in September
Johannesburg, South Africa

Average temperature in September - Johannesburg, South Africa
  • Average high temperature in September: 22.8°C

The warmest month (with the highest average high temperature) is January (25.6°C).
The month with the lowest average high temperature is June (16°C).

  • Average low temperature in September: 9.3°C

The month with the highest average low temperature is January (14.7°C).
The coldest months (with the lowest average low temperature) are June and July (4.1°C).

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Average humidity in September
Johannesburg, South Africa

Average humidity in September - Johannesburg, South Africa
  • Average humidity in September: 47%

The month with the highest relative humidity is February (70%).
The month with the lowest relative humidity is August (46%).

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Average rainfall in September
Johannesburg, South Africa

Average rainfall in September - Johannesburg, South Africa
  • Average rainfall in September: 27mm

The wettest month (with the highest rainfall) is January (125mm).
The driest month (with the least rainfall) is July (4mm).

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Average rainfall days in September
Johannesburg, South Africa

Average rainfall days in September - Johannesburg, South Africa
  • Average rainfall days in September: 3.8 days

The month with the highest number of rainy days is January (15.9 days).
The month with the least rainy days is July (1 days).

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Average daylight in September /
Average sunshine in September
Johannesburg, South Africa

Average daylight in September / Average sunshine in September - Johannesburg, South Africa
  • Average daylight in September: 11h and 5min

The month with the longest days is December (Average daylight: 13h and 48min).
The month with the shortest days is June (Average daylight: 10h and 30min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is September (Average sunshine: 9h and 24min).
The month with the least sunshine is March (Average sunshine: 7h and 42min).

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Average UV index in September
Johannesburg, South Africa

Average UV index in September - Johannesburg, South Africa
  • Average UV index in September: 9

The months with the highest UV index are January, February, March, November and December (UV index 12).
The months with the lowest UV index are June and July (UV index 5).

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Johannesburg, South Africa

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