Ok, last week in California, we had a heat wave. Yet, when I was driving, I noticed motorcycle riders still wearing jackets. I know they’re for protection if the motorcycle skids out, but with the helmet, how do they avoid dropping from heat exhaustion?
As long as you keep moving, it’s not bad. It feels worse when you stop but unless it’s for a long time you won’t be in trouble.
I used to wear full leathers in all types of weather, uncomfortable at times but nothing else resists abrasion as well if you go down.
The helmet actually isn’t as hot as you think. The same padding that protects against a fall also provides decent insulation.
Most motorcycle jackets these days have venting to aid in cooling off when you’re moving, even the leather ones. Personally I’ve got a mesh jacket, which doesn’t look as good on a cruiser as a leather jacket, but it’s almost completely open to the air save for the padding.
That said, while I’m okay on the bike, I get a little lightheaded from the heat after I get off the bike and start trying to cool down. But this is in ~110 degree weather, so it could be a lot worse.
. There is alot that a leather jacket 'protects ’ a rider from aside from if the bike goes down . There’s small pebbles that fly up from the passing traffic , swarms of insects. trash being tossed out passing windows etc… As it’s been posted , as long as your riding it stays pretty comfortable. My leathers have a removable thinsulate liner for colder moths.
A lot of riders (me included) would rather sweat than bleed. I laid a bike down once, a jacket would have kept me from scars and long term problems.
While I do feel odd shopping in a leather jacket when it’s 90 degrees outside, it would feel even odder having my flesh removed off by the pavement.
And Vermont is weird, it may be 90 in the sun on the highway, but if you get on a shady back road near water, the temp drops 20 degrees, and even wearing a leather jacket I get the chills.
Think of being outside on almost any day, with a 50 - 70 mph wind constantly blowing at you. Takes the heat right out of a person.
Don’t have a cite at the moment, but I recall a treatment for emergency heat stroke, especially for young athletes, was to put them under the rush of air created by the helicopter props that brought them to the hospital.
The average modern motorcycle jacket is actually constructed fairly differently from the typical fashion jacket, from a fit made for you to be leaning forward with your arms outstretched, to body armor inserts, special attachments to keep it from riding up and leaving your waist unprotected, etc. Here is an example of one with pretty standard vents and a zip out lining (scroll down).
I California it’s legal to ride between lanes, so it’s easy to keep a breeze blowing. As mentioned, most modern jackets have vents. Mine is mesh (with armor inserts), so it’s very comfortable in hot weather.
Unfortunately lane-splitting isn’t legal up here, so it reduces the utility of the motorcycle. Riders get stuck in traffic just like the cars do. And I can tell you the engine on the R-1 gets plenty hot when you’re sitting on top of it and not moving. Seattle hit 103º the other day, so it would have been very uncomfortable on the bike. I’ve been driving the Prius, which has air conditioning and gets better fuel economy (and on regular gas, instead of premium). With a 108.5 mile commute and an 80-mile butt, and not being able to split lanes, I can only ride recreationally now. 
Having riden bikes during the Greek sumer I wonder about the opposite: how can all those squids ride during 100F weather with shorts, a t-shirt, flip-flops and no helmet.
Having 100F air blowing constantly on you at 60+ mph is not a funny experience. It is like having a giant hairdryer in front of you. Any exposed parts of your body will dehydrate pretty quickly and if you are not wearing a helmet your eyes will dry out. So fully covered is the only way to go. As others already mentioned, when moving it is warm but not unbearable. And the alternative is much worse.
Sorry for the hijack but I’m wondering what a butt means in this context?
- F.I., non-biker
He can only tolerate the seat for 80 miles.
That’s correct. The R-1 is a fine bike; but it’s not as comfortable as others I’ve ridden, and I can only go about 80 miles in traffic before I can use a stretch.