Yes

you do need a jacket based on the weather in Braamfontein, Johannesburg, 2017, South Africa 1 second ago

Why? Because it's cool. Pleasantly cool, but cool!
58°F15°C & Clear

Wind is 4 mph6 km/h from the North, gusting to 11 mph18 km/h
July 1
7am59°F15°C4 mph7 km/h NorthClear
8am60°F16°C4 mph7 km/h NorthClear
9am60°F16°C4 mph7 km/h NorthClear
10am60°F15°C5 mph7 km/h NorthClear
11am58°F14°C4 mph7 km/h NorthClear
12pm55°F13°C4 mph6 km/h NorthClear
1pm52°F11°C3 mph5 km/h NorthwestClear
2pm50°F10°C3 mph5 km/h NorthwestClear
3pm48°F9°C2 mph3 km/h NorthwestClear
4pm47°F8°C2 mph3 km/h NorthwestClear
5pm46°F8°C1 mph2 km/h NorthClear
6pm45°F7°C1 mph2 km/h NorthClear
DateLowHighWindDayNight
June 3038°F3°C60°F16°C3 mph5 km/h from NorthClearClear
July 142°F5°C59°F15°C5 mph8 km/h from NorthwestPartly CloudyMostly Clear
July 245°F7°C63°F17°C9 mph14 km/h from NorthwestMostly ClearMostly Cloudy
July 341°F5°C56°F14°C6 mph10 km/h from SouthwestClearClear
July 437°F3°C62°F16°C6 mph9 km/h from NorthwestClearClear
July 541°F5°C63°F17°C9 mph14 km/h from WestClearClear
July 635°F2°C54°F12°C6 mph10 km/h from SouthClearMostly Clear

Yes

Low of 42°F6°C, High of 59°F15°C
Wind: 5 mph8 km/h
Precipitation: None

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