“is it better to stand in front of Hashem sweating in a hat and jacket in the 100 degree heat that can take away your concentration, or to daven without the hat and jacket and be able to concentrate better and be more presentable by not dripping with sweat?”
There aren’t many shuls around without air conditioning during the summer. Even if there is, I believe Rav Chaim Kanievsky answered your shaila – see above.