Not sure where in the Southeast you're located but here in Florida we head out early (6AM-7AM) and ride so we're finished by 10AM-11AM before it gets too hot. If you start your ride later in the day just take plenty of water and Gatorade. If I'm going out for a longer ride on a hot day I take my Camelbak.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.