Nothing to be afraid of adjusting a truss rod, it is not difficult or dangerous to your bass as long as you don't overdo anything.
Ernie Ball setup instructions here :- http://www.music-man.com/faq/music-m...-man-bass.html
You should only have to adjust the truss rod if it was set up to your liking before the weather changed. Probably more to do with the humidity than the temperature.
It is worth learning how to set your own bass up, it has saved me a small fortune in guitar tech fees (and fuel costs) in the last 40+ years. I check the setup and adjust if necessary every time I change strings.