Yes

you do need a jacket based on the weather in Chatswood NSW 2067, Australia 1 second ago

Why? Because just cool enough for a jacket, but not warm enough to ditch it!
56°F13°C & Clear

Wind is 4 mph7 km/h from the West, gusting to 12 mph19 km/h
September 11
7pm56°F14°C5 mph8 km/h WestMostly Clear
8pm60°F15°C4 mph7 km/h SouthwestMostly Clear
9pm62°F17°C3 mph5 km/h SouthwestMostly Clear
10pm63°F17°C2 mph3 km/h SouthwestPartly Cloudy
11pm65°F18°C2 mph3 km/h SouthwestMostly Clear
September 12
12am66°F19°C3 mph4 km/h SoutheastMostly Clear
1am66°F19°C5 mph8 km/h SoutheastClear
2am65°F18°C6 mph10 km/h EastMostly Clear
3am63°F17°C6 mph10 km/h EastMostly Clear
4am60°F16°C5 mph7 km/h EastMostly Clear
5am58°F14°C3 mph5 km/h EastMostly Clear
6am57°F14°C2 mph4 km/h EastPartly Cloudy
DateLowHighWindDayNight
September 1149°F9°C66°F19°C4 mph7 km/h from SouthMostly ClearPartly Cloudy
September 1249°F10°C69°F21°C5 mph8 km/h from EastClearMostly Clear
September 1350°F10°C71°F22°C4 mph6 km/h from NorthMostly ClearClear
September 1451°F11°C75°F24°C6 mph10 km/h from NorthwestPartly CloudyMostly Cloudy
September 1561°F16°C77°F25°C11 mph18 km/h from NorthwestMostly CloudyMostly Clear
September 1653°F11°C70°F21°C7 mph11 km/h from SouthClearMostly Clear
September 1750°F10°C69°F21°C6 mph9 km/h from NortheastMostly ClearClear

Yes

Low of 49°F10°C, High of 69°F21°C
Wind: 5 mph8 km/h
Precipitation: None

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