Full sized 1911, Combat Commander, Glock 23, S&W 3913, Kahr K9 or a Ruger LC9 in hot weather. All carried in leather or hybrid IWB holsters I made.
If the weather is slightly cooler and I can get by with a light jacket, any of the above or: a Glock 21, Beretta 92FS, Beretta PX4 Storm, Sig P220. Also all in IWB, enhanced/reinforced pancake or avenger holsters I made. A good double thick leather belt designed for concealed carry goes a long way when concealing the larger pistols.