Heat safety

Dehydration and hot weather

Short answer

Hot weather increases fluid loss through sweating. Thirst, dark urine, reduced urination, dizziness and a dry mouth can be warning signs.

What to do

  • Drink regularly.
  • Take extra care with babies, children and older adults.
  • Follow medical advice if fluids are restricted.
  • Get urgent help for serious symptoms.

Why it works

This advice follows NHS guidance and the underlying principles of dehydration and hydration.

Important exceptions

This page cannot diagnose anyone. Follow the linked health guidance and seek urgent help for emergency symptoms.

Sources & evidence

Reviewed 2026-08-21

  1. NHS: Dehydration

    Supports: Dehydration risks, signs, fluids and when to get help.

    health guidance · Accessed 2026-08-21