Well, it's not tomorrow yet, but I thought a couple of observations about weather would put the next weeks' conditions into perspective.
First, we went over there in "late spring", thinking that we were heading into Texas springtime. I packed one windbreaker, 1 light sweater, a turtleneck long underwear shirt (silk--very light), and a blouse and some shirts. A pair of leggings, a couple of pairs of hiking pants. In Texas springtime weather this would have been fine--even overkill.
Southern France and northern Spain in May don't even vaguely resemble Texas in the springtime. It is cold! If you are thinking of going at this time of the year, you should think of it as going to the northern third of the US for temperatures and weather. Take a fleece shirt!
I also found a couple more pictures of St. Jean to post:
The church interior