High Humidity and Temperatures
The effects of hot weather and high humidity can be experienced anytime, not just in the afternoon. When you are in a hot environment, your internal temperature increases. Your body reacts naturally by sweating copiously and radiating heat via the skin to reduce your internal temperature. These natural reactions are more effective if the number of electrolytes and fluids you consume is more than the amount you lose.
Overheating and dehydration can occur anywhere (indoors or outdoors). If you spend most of your day in a hot room with poor ventilation, your internal temperature can elevate to unhealthy levels.