This article is from the Bicycles FAQ, by Mike Iglesias with numerous contributions by others.
You should come to Europe prepared to get wet. Yes, it rains there in the
It can be hot at the lower elevations in the summer, if you sleep at higher
altitudes(>1000 meters) you may be able to beat the heat.
Some regions have predictable weather conditions such as the 15-20mph wind that
seems to always blow up the Sion valley from Maritgny towards Brig.
The best month to tour in the Alps is July. The weather is reasonably settled
and the days are warm. September is a good second choice, though the weather i
a bit more unsettled and it can turn cold and actually snow. Also, in
September, it is possible that the hotels at major ski resorts, like Sestriere
and Isola 2000, may be closed as they prepare for the upcoming season. Check
before heading up that next climb.
I would not recommend going to the Pyrenees Mountains during the month of July
(possibly even August). Even though there are a lot of 4000' climbs, the passe
are for the most part low altitude compared to the Alps(1500-2000 meters versus
2000-2700 meters) and because of this it is quite hot. A better time for the
Pyrenees is May, June or September. Also, I found the Pyrenees to be quite
beautiful but, I really like the ruggedness of the Alps and the roads in the
Pyrenees did not pass by much of this type of scenery(though it does exist via
August seems to be a bad time for a tour. All of Europe goes on vacation. Thi
means that the roads and accommodations are crowded and the air pollution is