I live in Phoenix, Arizona USA. It can reach temperatures of 115 degrees F or more in the summer months. Thankfully I have not yet had this speedo problem, but I am very concerned about it. My bike is a fairly early model built in December of '09, so if early speedos were defective I would think that I must have one of these, but I pray that I don't.
Same here with the summer weather. Temecula, CA hits over 100 for a lot of the summer months and then we have to deal with the Santa Ana winds during September and October. We had a few 120 degree days last year. At 25,000 miles I am still on my original speedo and my bike is an April '09 build. One thing I have done that might help is I have a thermostatically controlled exhaust fan in my garage that kicks on at 90 degrees. Without it it would hit well over 120 in my garage during summer months.