For the life of me, I continue to fail to see why people get so excited about the P6s. The trigger pull isn't very good compared to the commercial Sig offerings. The mags are hard to find and expensive. Aftermarket offerings for grips, holsters, etc are also rare. It'll also be a used gun with no warranty and an unknown service history.
Of the options listed, I would pick a brand new Sig P226 simply because mags will be more common and available than will be the case with the newer SW offerings. It also has a fairly long and successful service history.
Note that I did own a P6, and I even had plenty of mags for it, I traded it for a Model 36 and was happy with the trade. The 3913/14 pistols on the used market cost about the same as a P6 and are actually a tad smaller than the surplus Sigs, mags and parts are cheaper and easier to come by, and the trigger will usually be better. A 3rd Generation hi cap auto will also be in the price range of a Sigma or a P6. I still have my 3914.
My personal Sigma is a .40 caliber. It makes a Glock look beautiful and seem refined. Oh, it works, and the rough pointy parts left molded onto the plastic were easy to take care of, but a Sigma is probably at its best for a first time gun buyer, someone on a very limited budget, or someone who hasn't been spoiled by other offerings. (There really are differences even amongst polymer pistols.) Different strokes for different folks. It's an inexpensive handgun that is as reliable as a more expensive one, but handling and refinements hint towards the inexpensive heritage.
I'm not sure what kind of handguns you are used to. If you are used to 1911s, you might have trouble with the location of the Sig's decocker. It also takes training to learn to use a TDA auto if you were used to a DAO, SA, or revolver.
I'm not sure why you'd not want to carry it daily, unless you have some other carry gun. Unfortunate things can happen in any area and if you could predict when, you'd just stay home that day. I'm dealing with the same climate you are, and I have no problems with carrying a full size steel 1911 so a P226 should be quite doable for someone of average build, the P6 is thinner and more concealable, but the P226 isn't that bad.
The one downside to carrying Sigs, except for certain models that they've changed it on as of late, is that blued models tend to have rather thin bluing and are prone to finish wear and rust. The older P6s will certainly have the older style finish.