Yes.
I carry as much gun as I can conceal and cooler temps means more things to hide bigger guns under.
I live in the Deep South and there's only so much clothes you can wear in the summer without standing out like a Sherman Button at a Georgia picnic. Cooler weather makes for a lot more variety in those cover garments. Around here, fleece jackets come out when it hits the 60's and if it drops to around freezing during the day, most folks around here dress like Nanook of the North.