Short answer
Water-resistance ratings are lab test pressures, not safe diving depths. 30m (3 ATM) means splash-resistant only. 50m (5 ATM) is fine for hand-washing and light rain. 100m (10 ATM) is suitable for swimming. Water resistance weakens with age and after the back is opened, so have the gaskets checked.
What each rating means
- Water Resistant / 30m / 3 ATM: splashes and rain only. Don't swim or shower with it.
- 50m / 5 ATM: hand-washing, rain and light water contact. Not ideal for swimming.
- 100m / 10 ATM: swimming and surface water sports.
- 200m / 20 ATM and above: snorkelling and serious water sports.
Tips for monsoon and humid weather
Keep the crown pushed in, avoid hot showers with your watch (heat and steam affect the seals), and wipe the watch dry after rain. If you see fog under the glass, get the watch checked straight away.