Gear will always be a compromise for the hottest and coldest/wettest days.

I have wrestled with one piece rainsuits back in Europe and will never own anything one piece again, such a PITA to put on and take off over riding gear.

I am currently using a BMW Rallye 3 jacket and either BMW City pants (heavy denim with good armour which I wore in South America with Gore-Tex rain pants) or Klim Traverse pants which are Gore-Tex.

The Rallye jacket has a zip in Gore-Tex liner, but to be honest its a waste of time, BMW missed the boat and instead of making a nice zip in jacket with hand warmer pockets and branding on it, they have a plain insert with no external pockets or roll away hood. Why would I bother faffing around with this when I can wear my Mountain Equipment Paclite jacket with lots of external pockets and a roll away hood? - which is much more practical than the liner on or off the bike, it also fits outside or inside the Rallye jacket. The Rallye jacket is good, plenty of air vents, pockets and a hydration bladder pocket built in, I prefer this to wearing a separate hydration pack personally, it is quite a heavy jacket though (it has full back armour) and when its 42C and you stop in the sun at some lights for a few minutes you still cook.

I wore the Klim Traverse pants this Summer on the TCAT sections in BC, we had temperatures of 37C or more, hot and bloody dusty, they are never going to vent like a mesh pant, but with the front thigh vents and rear 'exhaust' vents open they do vent surprisingly well, you can get some good airflow over your Femoral arteries, which does help to cool you off, lower leg ventilation is non existent, but if you are wearing motocross or fairly high leg boots then its fairly pointless anyway. When it was cold or raining, zip those vents up and they were totally windproof and dry, I was fairly impressed with them overall. I just wore some swimming shorts under these for the whole trip, which was handy at lakeside lunch stops, go for a dip in the cool lake, put the riding pants back on with wet shorts underneath and enjoy being cool for an hour or so whilst riding in the afternoon.

Separate Gore-Tex waterproofs which can be worn off the bike (for hiking and camping) and well ventilated riding gear are the way to go, but having a pair of Klim or similar Gore-Tex pants in the closet are a good option occasionally.

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Cheers
Grif

'11 KTM 450 EXC
'09 Suzuki DR650
'00 Discovery Series 2 V8
'95 Defender 90 300 Tdi Overlander
http://gipperstravels.blogspot.ca