Some practical things to consider before discussing the June and September below:
- I suggest tour members bring a range of clothing that you can layer if the weather turns cold. The weather in the mountains can be unpredictable. Snow is possible even in July. We are able to leave excess gear and clothing at our base hotel. So I usually make a final adjustment to my gear based on the weather forecast issued on the last day at our base hotel. Then I simply leave any excess items at the hotel while away on tour.
- Morning temperatures are generally 20F – 25F cooler in the morning when we head out than they are by mid day.
- The temperature tends to drop approx 10F for every 1000 meters of height we go up. So if it is 70F at the bottom of a pass, it may be 45F – 50F at the top of a high pass at 2400 – 2700 meters. If we start out in the morning when it’s cooler and hit a high pass before the mid-day warmth it can definitely be a bit chilly at the top.
- Certain areas like the lakes region in Italy, at the southern edge of the Alps, or southern France can be 10F + warmer than the full mountains immediately to the north.
- SO – Bring a range of clothing suitable for varied tempeartures
June weather for the last few years has been great. Daytime valley temperatures have been in the low to mid 70’s frequently getting into the low 80’s(F). Morning temps are usually in the low 50’s. Temperatures warm up quickly and we are usually shedding layers by 10:30AM – 11:00AM. Reading daylight lasts until 8:30-9:00PM, perhaps one to two days of rain out of 10.
It’s great weather for kicking back at the top of a pass sans motorcycle jacket, soaking up the rays, and enjoying a cappuccino and apple strudel (my favorite snack). You can frequently go outside after dinner and sit at the cafe table in your shirtsleeve while people watching and having an after dinner drink.
September sees shorter days. Reading daylight ends between 6:00-6:30PM. The temperatures at 8:00AM will be mid 40’s, low 50’s getting up to the mid 60’s low 70’s during the day. It might rain two or three days out of ten (although in 2003 we had 12 days of perfect June-like weather).
Sometimes there is snow at night at the higher elevations, more so on the Swiss or Austrian trip than the Italian tour, which leaves the mountains dusted with white when you wake up in the morning. Occasionally, a rainy day in the valley will be wet snow at the top of a pass. However, the snow is usually just a nuisance and does not accumulate on the road.
The trade-off for going in September (shorter days and cooler temperatures compared to June) is that the tourists and vacationers are all gone. The foliage is changing, the shops and museums are open and you’ve got it all pretty much to yourself and the Euro bikers who are still out in force on the week ends.
I tend to run the Swiss/Italian tour in late June because the high Alps (TOP 10+) can still be snow blocked in mid-June. The Italian Alps seem to open up sooner, usually by mid-May. As I’ve said elsewhere in this website keeping our tour group to 9 bikes or less has several advantages including flexibility.
One September we awoke in Le Prese Switzerland with the intention of doing a loop over the Bernina Pass. However, while it was dry where we were the mountaintops around us, which had been bare the day before, were covered with snow. The Bernina Pass had received more than a foot of snow overnight and was still clearing out from under it. Our small group was able to change routes and hotels seamlessly for that day and got back on track the following morning.
I’ve been riding in the Alps for more than 30 years and I have only changed my itinerary two or three times due to weather.