at 42miles round trip with the temp on the way home often over 100 here in Dallas I have leard 2 things, one carry 2 large water bottles on the bike and drink 4-6 throughout the day (including the 1 to 2 from the morning commute) I also usuly drink 1-2 of thoes during the day mixed witha low cal electrolyte replacemtnt like propel. One home I drink at least 2 more, and 1-2 barley pops to add some more electrolytes.

I wear baggy riding shorts and a jersey every day. The jersey is to carry my helmet light battery, but it is also cooler than a cotton shirt..