No

Why? Because you should be inside at home! #StayHome

But if you absolutely had to go out to get groceries, medication or other essential travel, No, you don't need a jacket.

Based on the weather in São Paulo, State of São Paulo, Brazil as of May 25, 2020 11:03am local time.

Now

Clear
Temp: 62°F17°C
Wind: 15 MPH24 KPH
Precipitation: None

Today

Next 2 hours: No

Next 4 hours: No

Next 8 hours: No

Tomorrow

Yes

Clear throughout the day.
Low of 49°F10°C, High of 70°F21°C
Wind: 9 MPH14 KPH
Precipitation: 4% rain