Yes

you do need a jacket based on the weather in Adelaide SA, Australia 1 second ago

Why? Because it's cool. Pleasantly cool, but cool.
58°F14°C & Clear

Wind is 9 mph14 km/h from the SE, gusting to 18 mph29 km/h
April 30
5am56°F13°C9 mph14 km/h SEClear
6am56°F13°C8 mph14 km/h SEClear
7am55°F13°C8 mph13 km/h SEClear
8am55°F13°C8 mph13 km/h SEClear
9am54°F12°C8 mph13 km/h SEMostly Clear
10am54°F12°C8 mph13 km/h SEMostly Clear
11am53°F12°C8 mph12 km/h SEMostly Clear
12pm52°F11°C7 mph11 km/h SEMostly Clear
1pm51°F11°C7 mph11 km/h SEMostly Clear
2pm51°F10°C6 mph10 km/h SEMostly Clear
3pm50°F10°C6 mph10 km/h SEMostly Clear
4pm49°F10°C6 mph9 km/h SEMostly Clear
DateLowHighWindDayNight
April 2950°F10°C62°F17°C10 mph16 km/h from SEClearMostly Clear
April 3049°F10°C65°F18°C9 mph15 km/h from SEMostly ClearClear
May 152°F11°C69°F21°C9 mph14 km/h from SEMostly ClearMostly Clear
May 252°F11°C70°F21°C5 mph9 km/h from SEMostly ClearClear
May 351°F10°C71°F21°C4 mph6 km/h from SMostly ClearClear
May 451°F11°C72°F22°C5 mph7 km/h from SClearClear
May 553°F12°C72°F22°C4 mph7 km/h from SMostly ClearMostly Clear

Yes

Low of 49°F10°C, High of 65°F19°C
Wind: 9 mph15 km/h
Precipitation: None

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