I was understanding when my PT Pro+ (2008 model, wired) would conk out 10 minutes into a ride below 32F -- this is below the stated operating temps. I did wonder, however, because I know people who have no problem using their (usually older) wired models down into the 20s.
I just got back from a ride in 38-40, though, and the PT made it about 20 minutes before showing "---". I've replaced batteries in both the hub and the head unit a couple of times. Everything begins to work perfect within 5 minutes of being inside and warm, which seems way too quick to actually warm up the batteries in the hub.
Any ideas? Is this normal behavior? Time to contact Saris?