What are the pros and cons of sunscreen vs. protective clothing? I have decided that, lack of sunburn aside, I need to get back to being pretty serious about UV protection.  I've been sloppy about it for a few years, and would like to not continue inviting skin cancer.

I'm on my bike for 90 to 120 minutes every day, about 45 minutes in the morning and 55 minutes in the evening.  But, I'm in Austin, which means intense ambient heat and intense sun during the summer.  Sometimes I resent stop lights because they leave me sitting in direct sunlight with absolutely no air flow to cool me down.  Sometimes it's so hot that doesn't do any good, anyway.

So far as I see it, my options are to lather up my arms, legs, and face with sunscreen twice a day, adding on a hat beneath my helmet (or getting a solid helmet); or to get some of the UV-protective clothing like what Izumi makes and wear that on most of my rides, though that means extra cloth on my arms, legs, and hands, and thus more gear that I have to cope with.

Clothing appeals from a reusability standpoint.  It might also help by reflecting more sunlight and thus more heat.

Sunscreen appeals from a "not putting on cloth that traps heat" pespective.

So, in bright/hot areas, which is more comfortable?  Should I just try both and see which I find more comfortable?  Even more importantly, which provides adequate protection?

And, if parts of my body are not tanning at all (such as, under my shirt), am I actually getting adequate protection there?
Clothing is a good choice for sun block while cycling. Unlike walking or standing still, there's always a breeze as long as you are pedaling which increases comfort. Long sleeves and long pants may be comfortable on a bike in hot weather even when they are uncomfortable indoors or walking outdoors. 

Pros for Sunscreen as sun protection while biking


It's invisible.
You can wear whatever you want.


Pros for clothing as sun protection while biking


Unlike sunscreen, it doesn't wear out after 80 minutes. You are never left wondering if it's time to re-apply or not.
While you may find that your sunscreen has run out half-way through a multi-hour ride (as I recently did), you are less likely to find yourself unexpected naked half-way through a ride. 
Regular clothing often has some amount of UV protection. While you might need to opt for full-coverage clothing, you don't necessarily need special clothing
Doesn't involve covering your skin in chemicals.
Don't have that covered-in-sunblock feeling at the end of a ride. 


Here's a photo of clothing-as-sunscreen before I departed with a friend on a 114 mile day on loaded touring bikes:



On a trip this past weekend I decided to spray-on sun-block instead. We I went to re-apply some half-way through the trip, I found the canister was empty. Sunblock-Fail.