Yes

you do need a jacket based on the weather in Decatur, IN 46733, USA 1 second ago

Why? Because it's cool. Pleasantly cool, but cool and there are strong winds blowing out there!
57°F14°C & Cloudy

Wind is 14 mph22 km/h from the South, gusting to 27 mph44 km/h
April 18
8am58°F15°C16 mph26 km/h SouthWindy
9am62°F16°C19 mph30 km/h SouthWindy
10am66°F19°C21 mph34 km/h SouthwestWindy
11am69°F21°C25 mph41 km/h SouthwestWindy
12pm73°F23°C24 mph39 km/h SouthwestWindy
1pm75°F24°C25 mph40 km/h SouthwestWindy
2pm77°F25°C22 mph35 km/h SouthwestWindy
3pm79°F26°C22 mph36 km/h SouthwestWindy
4pm79°F26°C22 mph36 km/h SouthwestWindy
5pm78°F25°C21 mph34 km/h SouthwestWindy
6pm77°F25°C19 mph31 km/h SouthwestWindy
7pm74°F24°C19 mph31 km/h SouthwestWindy
DateLowHighWindDayNight
April 1854°F12°C79°F26°C21 mph34 km/h from SouthwestWindyRain
April 1951°F11°C68°F20°C10 mph16 km/h from WestRainRain
April 2046°F8°C61°F16°C15 mph23 km/h from EastRainDrizzle
April 2149°F10°C65°F18°C20 mph33 km/h from SouthwestRainPartly Cloudy
April 2242°F6°C67°F19°C7 mph12 km/h from WestMostly ClearClear
April 2349°F9°C74°F23°C6 mph10 km/h from SouthwestMostly ClearMostly Clear
April 2452°F11°C76°F24°C6 mph10 km/h from SoutheastDrizzlePartly Cloudy

Yes

Low of 51°F11°C, High of 68°F20°C
Wind: 10 mph16 km/h
Precipitation: 75% rain

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