People that are new to CCW tend to over carry. After a while, carrying too much stuff gets bothersome, and after a while you start looking for smaller, lighter options.
The average number of rounds fired in a civilian self defense incident is 2 rounds. In real world shootings with modern ammo, there really isn’t that much end result difference between 9mm, .40S&W, and .45ACP. I can show the numbers if anyone is curious. Shot placement counts more than anything.
You need a small weapon, because after a while that is all you want to carry. I tend to use an inside the waistband holster, which for a very hot climate is one of your better choices. My personal preference for something I’m going to be wearing concealed in an IWB holster is for something with a positive, manual safety. Unfortunately, that narrows your choices down quite a bit nowadays. If cost isn’t too much of an issue, look at the S&W M&P Shield, or the Sig P938 for a couple of choices to get you rolling. Much smaller than that you are looking at guns like the Ruger LCP.