September weather forecast and climate
Cape Town, South Africa

Cape Town, South Africa, with the surrounding calm clear waters and several mountains
Cape Town, South Africa, with the surrounding calm clear waters and several mountains

Weather in September

September, the first month of the spring, in Cape Town, is also an enjoyable month, with average temperature fluctuating between 10.9°C (51.6°F) and 18°C (64.4°F).

Temperature

In September, the average high-temperature is relatively the same as in August - a still enjoyable 18°C (64.4°F). The average low-temperature, in Cape Town, is 10.9°C (51.6°F).

Humidity

June, August and September, with an average relative humidity of 74%, are most humid months.

Rainfall

In September, the rain falls for 11.7 days. Throughout September, 37mm (1.46") of precipitation is accumulated. Throughout the year, there are 111 rainfall days, and 435mm (17.13") of precipitation is accumulated.

Sea temperature

July through September, with an average sea temperature of 15.3°C (59.5°F), are months with the coldest seawater in Cape Town.
Note: For most, swimming in 15.3°C (59.5°F) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 21°C (69.8°F) to 15°C (59°F).

Daylight

In September, the average length of the day is 11.9h.

Sunshine

The average sunshine in September is 8h.

UV index

May through September, with an average maximum UV index of 4, are months with the lowest UV index in Cape Town, South Africa. A UV Index of 3 to 5 symbolizes a moderate threat to health from the exposure to the Sun's UV rays for ordinary individuals.
Note: The daily maximum UV index of 4 interpret into the following advice:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the temperature in September in Cape Town?

The average high-temperature, in September, is 18°C (64.4°F), while the average low-temperature is 10.9°C (51.6°F).

What is the most humid month in Cape Town?

Months with the highest humidity in Cape Town, South Africa, are June, August and September, with an average relative humidity of 74%.

What is the average humidity in September in Cape Town?

In September, the average relative humidity in Cape Town is 74%.

How much does it rain in Cape Town in September?

In Cape Town, in September, it is raining for 11.7 days, with typically 37mm (1.46") of accumulated precipitation.

What are the months with the coldest sea water in Cape Town?

July through September, with an average sea temperature of 15.3°C (59.5°F), are months with the coldest seawater in Cape Town, South Africa.

What is the sea water temperature in September in Cape Town?

In September, the average sea temperature in Cape Town, South Africa, is 15.3°C (59.5°F). Swimming in 15.3°C (59.5°F) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 21°C (69.8°F).

What is the average length of the day in September in Cape Town?

The average length of the day in September in Cape Town, South Africa, is 11.9h.

How many hours of sunshine does Cape Town have in September?

In September, the average sunshine in Cape Town, South Africa, is 8h.

When is the lowest UV index in Cape Town?

Months with the lowest UV index are May through September, with an average maximum UV index of 4.

How high is the UV index in September in Cape Town?

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from the exposure to the Sun's UV rays.

Average temperature in September
Cape Town, South Africa

Average temperature in September - Cape Town, South Africa
  • Average high temperature in September: 18°C

The warmest month (with the highest average high temperature) is February (26.1°C).
The month with the lowest average high temperature is August (16.6°C).

  • Average low temperature in September: 10.9°C

The month with the highest average low temperature is January (17.7°C).
The coldest months (with the lowest average low temperature) are July and August (10.2°C).

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Average pressure in September
Cape Town, South Africa

Average pressure in September - Cape Town, South Africa
  • Average pressure in September: 1019.6mbar

The month with the highest atmospheric pressure is July (1022mbar).
The month with the lowest atmospheric pressure is February (1013.4mbar).

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Average wind speed in September
Cape Town, South Africa

Average wind speed in September - Cape Town, South Africa
  • Average wind speed in September: 15km/h

The windiest month (with the highest average wind speed) is January (17.6km/h).
The calmest month (with the lowest average wind speed) is May (13.4km/h).

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Average humidity in September
Cape Town, South Africa

Average humidity in September - Cape Town, South Africa
  • Average humidity in September: 74%

Months with the highest relative humidity are June, August and September (74%).
Months with the lowest relative humidity are February, April and December (68%).

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Average rainfall in September
Cape Town, South Africa

Average rainfall in September - Cape Town, South Africa
  • Average rainfall in September: 37mm

The wettest month (with the highest rainfall) is June (98mm).
The driest month (with the least rainfall) is February (7mm).

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Average rainfall days in September
Cape Town, South Africa

Average rainfall days in September - Cape Town, South Africa
  • Average rainfall days in September: 11.7 days

The month with the highest number of rainy days is June (13.8 days).
The month with the least rainy days is February (4.9 days).

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Average sea temperature in September
Cape Town, South Africa

Average sea temperature in September - Cape Town, South Africa
  • Average sea temperature in September: 15.3°C

The best month for swimming (with the highest average sea temperature) is January (18.5°C).
The coldest months (with the lowest average sea temperature) are July, August and September (15.3°C).

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Average daylight in September /
Average sunshine in September
Cape Town, South Africa

Average daylight in September / Average sunshine in September - Cape Town, South Africa
  • Average daylight in September: 11.9h

The month with the longest days is December (Average daylight: 14.4h).
The month with the shortest days is June (Average daylight: 9.9h).

  • Average sunshine in September: 8h

The month with the most sunshine is December (Average sunshine: 11.1h).
The month with the least sunshine is June (Average sunshine: 6h).

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Average sunshine days in September
Cape Town, South Africa

Average sunshine days in September - Cape Town, South Africa
  • Average sunshine days in September: 16 days

The month with the most sunshine days is January (23.1 days).
The month with the least sunshine days is June (14.6 days).

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Average UV index in September
Cape Town, South Africa

Average UV index in September - Cape Town, South Africa
  • Average UV index in September: 4

Months with the highest UV index are January, February and December (UV index 6).
Months with the lowest UV index are May, June, July, August and September (UV index 4).

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Average cloud cover in September
Cape Town, South Africa

Average cloud cover in September - Cape Town, South Africa
  • Average cloud cover in September: 33

The month with the most cloud cover is June (Cloud cover 34).
The month with the least cloud cover is February (Cloud cover 15).

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Average visibility in September
Cape Town, South Africa

Average visibility in September - Cape Town, South Africa
  • Average visibility in September: 10km

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).

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