Yes

you do need a jacket based on the weather in Denver, CO 80218, USA 1 second ago

Why? Because it's cool. Pleasantly cool, but cool!
57°F14°C & Mostly Clear

Wind is 3 mph5 km/h from the Northwest, gusting to 8 mph13 km/h
September 16
6am57°F14°C3 mph6 km/h NorthwestMostly Clear
7am55°F13°C4 mph7 km/h NorthwestMostly Clear
8am54°F12°C3 mph6 km/h SouthwestMostly Cloudy
9am54°F12°C4 mph7 km/h SouthwestMostly Cloudy
10am58°F14°C3 mph6 km/h SouthMostly Cloudy
11am64°F18°C3 mph5 km/h SouthwestMostly Cloudy
12pm70°F21°C2 mph4 km/h WestMostly Cloudy
1pm72°F22°C6 mph9 km/h NorthMostly Cloudy
2pm74°F23°C9 mph15 km/h NorthMostly Cloudy
3pm76°F25°C11 mph18 km/h NorthPartly Cloudy
4pm77°F25°C11 mph18 km/h NorthPartly Cloudy
5pm76°F25°C11 mph18 km/h NorthMostly Cloudy
DateLowHighWindDayNight
September 1654°F12°C77°F25°C7 mph11 km/h from NorthMostly CloudyPartly Cloudy
September 1751°F11°C71°F22°C6 mph10 km/h from NortheastPartly CloudyPartly Cloudy
September 1850°F10°C71°F22°C4 mph7 km/h from NortheastMostly ClearMostly Clear
September 1950°F10°C78°F26°C4 mph6 km/h from EastMostly ClearPartly Cloudy
September 2052°F11°C82°F28°C4 mph6 km/h from SouthMostly ClearPartly Cloudy
September 2157°F14°C83°F28°C6 mph10 km/h from NorthwestMostly ClearMostly Clear
September 2256°F14°C83°F28°C5 mph8 km/h from EastClearClear

Yes

Low of 51°F11°C, High of 72°F22°C
Wind: 6 mph10 km/h
Precipitation: 20% rain

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