bogydave

Last March I rode in 86°, full sun, slight wind, 44 miles.
That’s about my max over 20 mi.
One section was up hill , with the breeze so no sweat/wind cooling effect. Did a few loops up 1/2 mi/down an 1/8th
2 bike bottles & one in the jersey.
Pitt stop at mile 10, water fountain, drink & dump on body head to waste.
Barely enough water to get home.

I don’t go if it’s over 90° & full sun,
Evening & shorter rides.

caloso

During the summer in Sacramento, it is typically over 100F/38C for the afternoon commute.

Biker395 

It depends on the humidity. But for me in even a dry heat, this was too much. Ain't doing that again.

Doug64

On long tours my wife and I have ridden for up to 2 weeks in temperatures reaching 109F (43C). Timing and pace is everything on those days.

Steve B.

I’m good to high 80’s in high humidity, max.

I’ve ridden hi 90’s in 7% humidity, nowhere near as ucomfortable,

dieselgoat

I have yet to see a temp too hot for me to ride. I live in the south (U.S) where it typically reaches mid to upper 90s and commonly over 100 with extremely high humidity. Rather ride in that any day than anything less than 40 degrees.

Bmach

+1 with have not found temp or humidity level that won’t ride in.

JanMM

Don't recall ever not riding because of high temps/humidity. That's primarily in Central and Southern Indiana and an 8-year stint in metro Atlanta area.

Carbonfiberboy 

Long pass climbs at over 100° get to be a bit much. Still rideable, but trickier. Have never encountered temps over 104° out here, but rode in that too. In those temps it's too hot for me to ride continuously for long distances. I can't drink enough water to keep up.

rydabent

For me some where over 100. OTOH I hate riding when its below 65.

jon c. 

Haven't encountered 'too hot' and I love riding when its in the mid 90s. I agree that anything under 65 holds little appeal.

79pmooney

I raced many moons ago on a New England 98 & 98 day. I actually enjoyed it. Miserable enough that it slowed the race a lot. Being tall and skinny with lots of surface area for my weight - normally a huge curse on flat ground - I go t to enjoy my far greater cooling surface than most. I did much better than expected.

A few years ago, we had days of well over 100F each day but very dry. Rode home from work. Rode between two buildings and got hit with a blast of heat like an over door was opened on me.

I am finding as I age, my body enjoys riding in real heat less and that I start feeling faint or sick if I don't watch it.

Ben

bogydave

Takes a while for my body to learn to sweat, big climate & temp swing for me.
I have to work up slow to rides in the 80°s
An 80° day in Alaska is rare.

But that's OK,
I tried studs, & layers, fogged/iced up glasses, shoe booties......
SoCal riding is much more fun in the winter

canklecat

I've ridden up to 60 miles on summer days when the midday temp was over 100F. A friend routinely rides full centuries in that heat. I'm 60. I think he's mid-50s.

It's possible for a reasonably healthy human to get accustomed to it. But there's a methodology to heat adaptation based on research. There are articles available online in medical and research journals. Skip the watered down summaries in sports magazines and pop-health nonsense in woo journals. You can't just "harden the eff up" with a tough guy attitude or rush it. Doesn't work that way. It takes time and careful approach.

I started in early June last summer. With the exception of one bout with dehydration the first week -- oddly enough on one of the coolest, overcast days of the summer (I didn't drink enough or use electrolytes -- I've done both since that episode) -- I made steady progress and was able to ride faster, farther and more difficult routes through the summer and early autumn when it's still very hot in Texas.

And I'll need to start over in late spring. Heat adaptation doesn't last and needs to be refreshed regularly.

Some studies include experiments with training in artificially induced heat. The sample group was limited and the results were inconclusive. Lacking direct sunlight on the body, I'd guess we'd need not only a hot room but also fans to generate wind comparable to what we'd experience outdoors to emulate the dehydration effect. And the humidity would need to be adjusted to emulate the outdoor riding environment. But it probably helps to ride a trainer indoors in a hot room, just to maintain a level of heat adaptation for summer.

Machka 

I've done numerous rides of various lengths from a 6 km commute to a 600 km randonnee in temps above 30C (86F) ... and portions of those rides in temps as high as about 40C (104F).

If I'm prepared and can keep my hydration and electrolytes in balance, I'm OK.

But, for example, I did DNF the Gold Rush 1200 one year at the 400 km point because the temps during that day were up in the 40C area, food and beverages were scarce, and after slogging up and down hills in that heat all day long, I finally had enough.

Doug64

Sometimes on tours there just isn't any choice about riding when it is hot.

Not much shade either, Oregon High Desert.

[


Sometimes you find shade and hang out until early evening when it cools a little.

Maelochs

Same here.

I tend to agree. I used to have no problem with any heat or humidity level--but I also used to ride daily, year-round, and didn’t have A/C at home.

Now I rarely feel daytime summer heat except on rides and I think my body is simply unable to adapt.

ptempel

I haven’t ridden in over 96F or so if I recall. Was still a little humid so was a bit brutal. I remember a guy yelling at me on a side street “it’s too hot!” However, I’ll take 50s and 60s F temps any day. You still don’t need much clothing and feel like you almost never sweat.

GadgetGirlIL

My hottest ride was 96 degrees that happened late September during 7 days of record setting heat that we had. Late September and that hot in northern Illinois? Ugh. I never was so glad to get back to my car and crank up the A/C.

I really am much more suited to exercise in cooler temperatures. I'm fine with cold weather (< 32 degrees).

locolobo13 

Commuting? Up into the 100 teens. Rarely lasts more than a week at a time here.

Longer rec rides? In the summers I start early. Often back home before the temp is over 110. Also in the summers I usually limit my weekend rides to less than 40 miles.

IMO acclimatization is the key. If you are outside daily then the temp change is gradual letting you get used to it. Learn to listen to your body too. Thirstier than normal? Dizzy? Your body's telling you to drink more or take it easy.

big john

It depends on the distance and the amount of climbing. It gets over 100 quite often here and for a shorter (25 miles) it's no problem. Make that 80 miles with 8000 feet of climbing and high heat becomes a problem.

scratchpaddy

I commute year-round here, which means weeks at a time with highs above 110°, and many mornings it doesn't drop below 90°. I remember one day, it was 117°, and I had to stop to help push a stalled car out of an intersection. No one else was willing to get out of their air-conditioned cars to help.

My commute is short, though. Anything more than 15 miles or so, I can't stay out long after sunrise. 95° isn't so bad before the sun comes up, but closer to noon, it's so hot it hurts. Even the brake levers get painful to touch.

Now, when I lived in Georgia, if it got above 90°, I was done. All the sweat in the world won't do you any good. I'll take a dry 115° over a sticky 95° any day.

pdlamb

"Too hot" is when I either run out of water, or can't chug enough water (and eat enough salt) to keep up with sweating. Note this depends on the length of the ride, grade, and winds; "too hot" most often occurs on long rides, climbing steep hills, and either stiff headwinds or a tailwind that just matches my speed while climbing.


The rest is just training.

DrIsotope

We routinely get several summer weeks of +110º, where the overnight low is in the upper 80s. I can do it, I just don't like it. So I get up and ride at 4am (when it's only 85º) and get home around sunrise. Because by 9am, it's 100º.

When I do have to ride in the heat of it, I make an effort to plot routes that minimize stopping. Even above 100º, constantly moving makes it slightly less terrible. But every stoplight is like being dropped into an oven. I measured the driveway at our house with the infrared pyrometer last year. The temperature of the air isn't the biggest problem-- it's the temp on the ground.



No thank you.

Biker395 

^ +1. You can ride in pretty hot weather so long as your're hydrated and you have a good breeze going by. But when you stop at a stoplight and you're just sitting there ... that's when it really gets nasty.