Hot Weather Water Calculator
Use the calculator for a practical estimate of extra drinking water when weather and outdoor time increase sweat loss.
Open hot weather calculatorHow heat affects hydration
Hot conditions can increase sweat loss, especially during activity. This tool applies a modest extra-water estimate for heat and time outdoors; it does not measure sweat loss and cannot replace individual medical advice.
Seek urgent medical care for symptoms of heat illness. People with fluid restrictions or medical conditions should get individual guidance before changing intake.