Sweat is just the body's process of shedding heat by evaporative cooling. It does not require any extra calories to produce sweat than it does to produce urine.
Good discussion. My take away reading both pros and cons of what is written is...body core temp likely doesn't change much aka if it did, it would probably do much harm. Of course delta T aka internal body temp relative to external temp can be dramatically different. When delta T is big, sweat results in an effort cool the body to maintain core temp. Perspiration itself doesn't result in additional caloric burn...or very modest if any affect.
So likely as stated, increased calorie burn in higher temp weather must be due to other factors. Not sure if mean heart rate goes up in the summer as I don't train with a monitor. I believe my diet is similar but perhaps not. I though perhaps the process of hydration had a flushing effect of fat in the body but most seem to think this is bogus or not material.
In any event, I am glad I am dropping weight. I am riding stronger as well. I suppose there could be a synergistic effect in play. Because I am becoming fitter coming off sedendary winter months, maybe my metabolism has sped up and I am naturally burning more calories. So I am changing based upon my riding regiment which is changing my metabolism. Which leads me full circle to....I need to move out of the Midwest and get in a climate I can ride more months out of the year. That way I can be more fit year around.
You can get a thermometer quite inexpensively at most pharmacies ... so take your temperature when you wake up in the morning, before you do anything active and before your shower. Take your temperature just before you head out on your ride. Then take your temperature during your ride, after you get all warmed up and start sweating.
So far, you're just using perception as your guideline, but you can track some real data.
-- body temperature (with your thermometer)
-- heart rate ... get your resting HR, your pre-ride HR, and your HR throughout the ride
-- distances you ride each day that you ride throughout a year. Use some method to record your rides over a year.
-- ride time ... how long did it take you to do each ride? total time? on-bike time?
-- calories consumed ... meticulously track your calories consumed for 3 weeks in the heat of summer, and again for 3 weeks in the chill of winter.
That must be pretty uncomfortable riding with that thermometer up your...
You might still do it that way, but I think most people use thermometers under their armpits, in their ears, or under their tongues ... depending on the thermometer you get.
Note that the "normal" temperature acquired by each of those methods is slightly different, but if you use a particular method consistently, you'll get decent data.
You perceive that you're losing weight in the summer. Why?
If you track the amount you eat in summer vs. winter, you might discover that you eat fewer calories in the summer vs. winter.
If you track the amount of cycling you do all year long, you might discover that you cycle more in the summer than in the winter.
If you make those discoveries, that would explain why you're losing weight in the summer.
You perceive you're working harder in the winter than you are in the summer. So track your HR for a few weeks in the winter and a few weeks in the summer, and see if your perception is indeed true.
You proposed a theory that your body core temperature might go up during an intense workout in hot temperatures ... so take your temperature and see if that actually happens.
It's not that complicated.
I spent some time in New Orleans drinking, boozing, hanging...sweating my ass off because it was so hot. I didn't lose one pound, in fact I gained some. I think the Op's metric is a little off.
“Man only likes to count his troubles; he doesn't calculate his happiness.”
-- Fyodor Dostoevsky
Quick, someone close this thread before someone mentions Lance... uh-oh, too late.