Hydration needs vary based on temperature, exertion, and trail conditions. A general rule of thumb is to drink about half a liter per hour of moderate activity in moderate temperatures. In hot conditions or during strenuous hikes, you may need up to a full liter per hour. Consider factors like altitude, humidity, and individual sweat rate when determining your water intake.
For longer hikes, plan out your refill points. Carry a lightweight water filter or purification tablets to ensure you have safe drinking water.