qcpmsame 

Summers here in the Central Gulf Coast, NW Florida, can be hot and humid almost every day from May through November. I watch my hydration while I am out riding, and I try and hydrate prior to going out, most of the mornings. I have seen ambient air temps of 100ºF+, while riding. The heat index here frequently reaches 110ºF+, so its a case of watching how I feel and drinking water or a drink mix (Scratch Labs) almost constantly.

What @DrIsotope said above, +1

Now though, I an drawing the limit at a low of 35ºF and a wind chill of 30ºF, not that it was asked, just what is going on right now.....

Bill

caloso

In NorCal we have a road race every August called Dunnigan Hills. Despite the name it's mostly flat and windy. One year the average temp was 95F with the peak at 109F according to my Garmin. Started with four bottles, drank them all on the first lap, I probably drank 10 in all, and was still dehydrated by the end.

https://www.strava.com/activities/17926617

Wildwood 

I hate any temps in the 90s or above. Lower temp limit, unless the ride is less than 30 min, is about 40*F and never on ice.
But it's Seattle, so those limits rule out less than 30 days a year. Mostly winter, when I'm skiing & hiking anyway.
Having lived within a few miles of the Pacific most of my adult life, i'm temperature spoiled. Not too hot, not too cold, just about right year round, given the season.

Have no desire to acclimatize to 100s or heat+humidity.

Ogsarg

I'm fortunate that where I live even in the hottest times, it is rarely more than high 70's in the morning and I can get in a good ride before it gets too hot, which usually isn't till near noon. I've had a few rides where it was 100F when I finished but that is the rare case. Usually it's mid 80's.

mercator

Trying to complete a century in southern Spain once, I had to call for a ride as the temps reached 43C (109F). I sat with my head under a fountain for half an hour and felt better but just could not pedal any further.

canklecat

Yeah, I wouldn't say I enjoy riding in the heat. Thyroid disease has caused problems with my heat tolerance. I just did it gradually and methodically this past summer to find out how much I could tolerate if I did it carefully. About 15 years ago when I hadn't yet been diagnosed with thyroid disease and treated, I had a bout with heat exhaustion and passed out while working outdoors in summer heat. So I've been very careful since then.

I got a late start on a couple of metric centuries this past summer, so I had to stop at a park with covered picnic tables and rest for about 30 minutes. That spot is at the peak elevation of that particular ride, so it's a convenient place to cool off before tackling the relatively easier return route. But it's all roller coasters so it always feels like climbing even though it's a gradual change in elevation over long distance.

Usually I prefer night rides in summer, unless I can get a really early start. If I don't start before 9 am it's gonna be hot well before noon.

CliffordK

We've had a few hot ones in the last few years.

Our typical summer day is around 80 to 85° F, but I've been out a few times over 100°. I think I did one ride of 150 miles or so in the heat, although it was only really bad for a few hours mid afternoon.

And, hit a couple of 20 mile or so rides last summer in 100°+ weather. Hot, but not unbearable.

Actually, driving in Missouri and Kansas in HOT weather without AC may have been worse, especially if I ever had to roll the windows up to answer the cell phone.

rob214

I live in southern Louisiana so I'm usually done by 11am or ride at night. high temp is not the issue it's usually how I feel that day after work. I'm a welder so I spend a lot of days being hot. now cold on the other hand......I love and so far for this southern boy 30F was a bit nippy for me.
rob

Maelochs

Heat I can dodge by riding at night. This freaking arctic air ....

bogydave

77° uphill with the wind today, like in a bubble
face started feeling hot but
was sweating a lot. ( for an Alaskan)
Amazing here in the desert, sweat don't drip, it evaporates fast

About a mile, much more & I'd have stopped.
then a cross wind then right turn into the wind,
For a cyclist to say this "felt soooo good to ride into the wind" but it did

Not always temp, conditions too can make it hot too.

Ball Bearing

High temps don't bother me much, as long as my feet don't heat up too much. My favorite hot weather shoes have vents in the front of the toe box and along the sole.

Barrettscv 

I can handle 90f if it's not excessively humid. 95f, or warmer weather causes me to experience heat-exhaustion like symptoms. It's difficult for the body to cool itself when the air temperature is similar to the body temperature.

Above 90f I slow the pace, drink extra fluids and rest during longer rides. Above 95f, I use the trainer in the basement.

StephenH

We ride through the summer here in the Dallas area, and you'll have occasional days topping 100 degrees.
100 oz Camelbak with water and ice, two bottles w/ water or Gatorade, and that's good for about 30 miles.
Keeping excess weight off your person helps a lot.
Living in a climate like that, as opposed to visiting from somewhere cool, helps, I assume.
Humidity makes a difference. But around here, usually, when the temperature goes high, the humidity isn't high at the same time. So you'll take off in the morning when it's 80 degrees and 100% humidity, and just be dripping sweat, but by afternoon, it's warmed up, humidity has dropped, and it's actually easier to deal with then.

Stormsedge

My hottest ride was a Metric in Texas...temp at the finish was 100...road surface 107. Hydration (over several days) is key, as well as nourishment, when the body is being brutally tasked. My riding partner heat stroked out on the same ride at mile 42.

fietsbob

Clifford is in the valley, I'm on the coast, rarely hits 80f here typically 60-70,, low in the 50's,

winter , high is 50, low 40,

rarely drops into the upper 20s, when it does, it is because of no cloud cover..




....

deacon mark

Never ran into weather too hot to ride. Just have seen stay off chip seal roars they melt and tar. Hotter the better but i have raynards syndrome too.

DaveQ24

The actual temperature is pretty irrelevant to me, dewpoint is the single most reliable marker of how I’m going to enjoy riding. If it’s in the oppressive range, 70 F and over, I’m probably not going to like it out there. Other measures of the perceived temperature, such as Accuweather’s RealFeel temperature, the Heat Index, etc. are decent indicators for me as well.

350htrr

I don't know what would be too hot to ride in, I do know I have ridden in 44*C/118*F for 66Kms and didn't stop because of the heat... Probably could have fried bacon & eggs on the blacktop...

B. Carfree

When I lived in the Sacratomato valley, triple digit temps weren't really an issue (normal summer day, as you said). However, the triple digit pollution standard index, now the air quality index, would slow me down in a hurry.

Two decades in the Willamette Valley and Oregon coast and I'm better acclimated to what used to be hypothermia-inducing temperatures. I don't know if it's age or not, but I'd much rather ride in temperatures in the 40's F than in the 100's these days.

Wileyrat

I'm fine to mid 90's with low humidity, but during our monsoon season I try to be done by 90. If I don't finish before that, it stops being enjoyable.

After work, I'll start a 25 miler in the mid 90's in low humidity, knowing the temps will drop a few degrees by the time I'm done.

Enjoyable is the key, I can go hotter, but I don't like to.

PaulH

Really no limit. Riding a bike is much less stress than walking, because of the faster flow of air. Given the choice of a mile walk to the subway or a five mile ride directly to work, the ride is faster, cheaper and less sweaty. Even back when my commute was 12 miles each way, 100 F was no problem. It's even easier with my current 5 miles each way. It's like asking, "how hot/cold is too hot/cold" to leave your house?

IronM

its the humidity here in the south USA that gets me. I did a race two years back where it was 93F and high humidity. I made it to the end, but was delirious and totally mistimed the sprint. It took forever to re-hydrate. Yeah; I'm never doing that again. Usually 92F is my cutoff, and even then I'm not gong to go hard. I do much, much better in colder temperatures. I absolutely love long winter rides!

IronM

Where summers are hot (90F+), exceptionally humid, and city air quality poor; I'll get up at 4:30 AM, throw on lights and ride then. I skip the 'code red' air, the traffic, and the oppressive heat.

Oldguyonoldbike

I imagine we're all pretty much acclimated to where we live. We get some pretty extreme weather here in Oklahoma, but more at the hot, dry and windy end of the spectrum. I've grown to be comfortable with that. I've ridden a couple of metric centuries with temps well above 100°F. If you're not willing to ride in 90+ temps then you won't be riding much for about half the year. The important thing is to keep hydrated.
On the other hand, I've only ridden a handful of times with temps below freezing, and hated it.

caloso

Yeah. Combine this thread with the cross wind century thread, and I'm thinking that if you won't ride in temps above 90 or in a crosswind, then you're pretty much not riding in Sacramento.