Another ally of the summer bicyclist is an icy-cold drink. Normally, I dislike iced drinks - they affect the flavor and the ice cubes always swarm up to your lips when you take a sip. However, ice is a must for hot days.
I have a great handlebar mounted cupholder, but I have transferred it to my Raleigh which I ride less often. I'm looking for something now that can sit in Blue Belle's front basket. In the meantime, I can slip a covered bottle into the closest corner of my tote bag and pull it out to sip on at stop lights.Some types of cups will splash in transport - watch out for uncovered vent holes or leaky lids. You want to drink your beverage, not wear it. Fill a travel mug up with water and shake it vigorously to test the splash factor.
I like to cold-brew coffee overnight and drink it on the way to work in the morning, crammed with as many ice cubes will fit. Believe it or not, they will be melted 4 miles later, as I reach my office building. Of course, there are many other good choices as well: water, lemonade, iced tea, juice, soda... And it's always a pleasure to stop somewhere, if you have the time, and enjoy a glass of beer, iced tea, or a refreshing gin and tonic with some friends. But that's for after work!