I'm starting to think about what clothing to take with me on this ride, especially considering the possibility of changeable weather conditions in the mountains.Last year on the 999 Miles ride in Southern Italy the weather was set fair, so I left my warmer waterproof/and reflective in the drop-bag, and suffered when the weather turned at the end.
I've luckily got an airlight down vest (bodywarmer) from my company Gant, which is light and packs down quite small. I think I'll take that for any emergency cool conditions and a fairly light but windproof waterproof (DHB) that I would use for all-day wet conditions, plus the PBP 2015 Reflective jacket, plus armwarmers and 'rainlegs' to keep the legs warm, and lightweight long-fingered gloves.
What is everyone else taking and perhaps whosatthewheel has some advice?
(I live in Italy, close to the center of the loop of Alpi 4000)
Don't forget the lapse rate: the route highest point is at about 2,770 m, the lowest almost at sea level, you can expect 18°C of difference just because of the height. You might have to face snow at Passo dello Stelvio (at the end of July it's improbable but not impossible) while the lowest part of the route, the Po Valley, can easily reach 36°C at daytime, and is usually very moisty to make things worse.
You'll meet really high mountain passes (2,000 m or so) in stages 1, 2, 6, 7 and 16.
The (optional) bag drop in Biella is at the end of stage 4 and 8, so it splits the route in three parts, but none of them is without high mountains, so you can't pick up/leave all your warm clothes at the bag drop, because you need them in all of the three parts.
My suggestion is to try and organize your ride so that you pass through the Po Valley (mainly stages 9 to 12) during the night/early morning, and on the contrary don't plan to ride in the late night in the mountains: apart from the cold, you would miss the scenery.