Gents, I know it's getting unbearably hot out there in the wilds of the District of Columbia. Now's as good a time as any to encourage you--strongly encourage you--not to take your jackets off when you stroll the streets.
A suit is a suit. It's built, designed, and cut to be worn as a suit. Suit pants don't fit the same as trousers, and they tend to be made out of suiting material rather than pants material. Suit pants without their jacket just look funny.
Another thing that just looks funny is wearing slacks, a tie, and a button-down with no jacket. It looks like your job requires you to wear a tie and you do so begrudgingly. It makes you look like a perfunctory wearer of clothing, like you're just going through the motions. Dress it up with a sportcoat.
Wearing a jacket and tie outside in the best as well as worst weather sends the message that you care about the way you present yourself because you have something of which you are proud enough to present--here, your personality, wit, and work ethic.
You may safely claim that I am showing you the steep and thorny way to heaven; after all, I pay to park downtown so that I do not have to sweat through my clothes on the Metro in the summer. For what it's worth, I make an exception for the Metro platform and cars on these nasty-humid days when the air just sits on you like an unwelcome demon of hate and bile and suffering. But once you disembark, or at least get aboveground, put your jacket back on.
Anyway, it could be worse. You could have to wear three-inch heels to work.