I noticed the calendar in my wife's run of SPARE PARTS as well. I looked through her settings and noticed her calendar widget was set to update every 15 minutes and it had the WEATHER option checked. I fixed those two things and her phone seems to be fine now.
I did find the weather option in the calendar, but I still can't find the calendar update interval settings. all i have under the calendar setting is: reminder setting, and calendar view settings. I see nothing in either of those to change how often it updates