Which City has Better Summer weather in your Opinion, Indianapolis,Indiana Or Denver, Colorado?

Since you asked for an opinion, I will give my personal opinion. I lived in Indianapolis for two years prior to moving to Denver. Denver gets my vote, no question.

Indianapolis although I would call it a tie. Denver has higher risks of floods and more cloudy days.

Winter though Indianapolis would win hands down due to no mountains to interfere with the weather and a very low risk of blizzards with warmer temperatures than Denver.

For me, it would be Denver as it is a bit cooler and usually much less humid. And the nights are more pleasant due to the lower humidity in the air.