when its really hot do you bike in early AM or late afternoon.
 

I find myself favoring getting out about 6:30 PM and taking along a light in case. Get out at 7 AM, I just might find myself getting back a little too late and it gets over 85 before I get back home. Go out at 7PM, I know the temperature is going down not up. All possible since it does not get dark until 9:30 PM.
In winter, I think i hate the cold, but then when it's near 90, not so sure.

My primary source of miles is commuting and I am originally from an area that is very warm in summer. Warmth is much easier for me to ride in than cold. To answer your question, no.

I live in Houston, Tx. I ride all times of the day, but prefer early morning rides, especially if I get out before sunrise. Last summer, I was on the road by 5:30am most mornings. It was great. I could skip putting on sunscreen and the number of joggers and cyclists in my local park was nil. I did have to get a much better light to ride in the dark (Cateye Tripleshot) and that made all the difference in the world for night time riding.

Last year, 20 miles was a long daily ride. This year, I always ride at least 25 miles and frequently do 40-45 miles. I rarely have time to do the longer rides in the morning, so do it in the afternoon, starting around 5pm. Its much hotter, but I've acclimated. If I get off late in the afternoon, I end up getting home after dark. I ride through a park that goes by a bayou and the bugs are terrible after dark. I also find that I have trouble going to sleep, if I exercise too late in the day.

Bob

Early morning rides for me means less wind, less traffic, better feeling the whole day after a morning ride.

I do start my recreational rides as early as possible on the weekends. Mainly to avoid the heat and keep my wife from complaining.

Another Houstonian here. When school's in session I commute about 6:45 am and 4:30 pm. I would ride in earlier, but can't get in the building. That afternoon ride is HOT and humid, but unavoidable!

My thinking is should you have a good light, what is wrong with getting back about sunset. Do an AM ride, one flat and it is maybe 100 degrees. I really get grumpy when it is hot /humid. My wife will vouch for that fact.

Sun comes up here about 5AM so I am usually out a little later. It has been in the 90's and above the last couple weeks and it sure feels good to ride when the temp is in the 60's, also nobody else is out and no traffic to worry about.
I despise riding in the heat, I would rather wear a jacket than get overheated.

Once again, a Houstonian.

Recreational... Late PM :D
Head out about 9 or 9:30 at night. It's just as humid, but much cooler.

As for sleep... I ride hard towards the end, and in general, so I'm pretty wasted and ready for sleep once I get home. The only problem is wanting to eat ALOT, and knowing i need to get to sleep.

Commute... 7:30am, and 5pm. Required hours. During the school year, I ride in at 3pm (yeah it sux), and ride home about 11 or midnight (awesome).

I ride in the early evening in the summer, 5:00p-6:00p. Mornings may be slightly cooler 75-85F but the humidity is way higher 10%-20%. For me it is better to ride at 93F and 53% RH than 85F and 80% RH. Down here the heat of the day burns off a bit of the humidity. Humidity not heat is my enemy.

I do the usual, start at 10 am and finish at 1-2 pm. Usually ride down to the coast where it is a bit cooler. The return gets very warm halfway back. If the temps are 100 plus, doesn't really bother me. I keep cool as long as I'm moving. I'm not a dripper so no problem.

The wife is a different story. She doesn't handle the heat well. She doesn't like getting out of bed earlier to avoid the heat, so she deals with it or just goes shopping.:D

When it is really hot and during the week, I tend to do my riding in the evening. This is primarily because I get up at 0500 and am generally at the office by 0700. It would be difficult to squeeze in a ride in the morning. Now on the weekends, I prefer early morning rides: much cooler and much less traffic.

I usually ride most mornings and quit just before noon when the sun is bearing above you. I get an average of 3 1/2 hours riding whenever I can and finish most rides with at least 50 miles to the bikes credit. I have taken few rides in the late afternoon but I can't match the mileage I record during my morning rides. I do need a good head light though if I wish to ride in the early evening more often just in case. But morning rides seems to be what my body desire, perhaps it's because I have more energy early than late in the day.

I like the heat, so anytime works for me, but I prefer early morning on the weekends and evenings after work during the week. Much for the same reasons as MillCreek.

Having lived in FL this was a big issue for me. After trying both many times, I found afternoon/evening rides to be much better, IMO.

Morning Rides: Relatively cool, but gets hotter and hotter as you go along. You have to worry about getting home to go to work (e.g. some stress).

Evening Rides: Starts hot, but gets cooler as you go along. Nothing, per se, to worry about getting back to (at least nothing that can't wait), so that stress is gone.

Having tried them both extensively, I much prefer evening rides.

I ride at noon when I get out of bed most days. I bet I'll be immune to the heat by the time the Hotter Than Hell comes around.

With little kids I have to grab alone riding time when my husband or a sitter are available. If I ride with the kids I avoid midday, when the UV rays are supposed to be worst and it is hottest, all other times are fair game.

I feel the heat much over 85, so 90 plus really cooks me. Regardless of humidity. Always been that way, just put me in a closed room above 85 that's humid and I will soon need a shower. Heat has always made me feel even a little dizzy like. I get out after 6 PM, that pretty much assures it will be under 85 at all times. Three ,1/2 hours of light now, that pretty much guraantees I will get back before dark.