Remember that thirst isn’t a good indicator of hydration. Once you are thirsty you are already low on fluid. People who are suffering from dehydration will experience an elevated heart rate during and after the run and urine that is dark yellow. Drink water consistently until the urine is clear. During your run drink between 4 and 8 ounces every 15 to 20 minutes of your run.
Runners can acclimate to the heat and humidity but it takes approximately 2 weeks for the body to run efficiently in warmer weather. Run during the early morning hours to avoid as much of the heat as possible. There may be higher humidity but the air will be cleaner because the ozone levels increase as the day progresses and decreases in the early evening. As a runner the times to avoid are between noon and 3 pm.