Dez, us desert rats have to run higher viscosities because of the heat involved.
Them Yankees have to use lighter oils because everything north of Texas is a frozen tundra wasteland 

I personally use Phillips X/C 25W60, the same oil that I use in my AgCat, during summer months.
In winter temps I switch to 20W50, same oil that I use in my Bellanca.
Both are aviation oils that are formulated for a lot of the same conditions...keeps crud trapped in the oil so it can be removed with an oil change (synthetics usually drop the crud and buildup occurs), has great corrosion prevention, withstands extreme heat without breaking down and releasing acids, and just like avgas, its production is held to exacting standards.