How to interpret pressure trends
- Fall of 1 hPa in 3 hours → Slight change, usually no concern
- Fall of 2–3 hPa in 3 hours → Moderate, watch weather
- Fall of 4–5 hPa or more in 3 hours → Rapid fall, possible storm approach
- Steady or rising → Generally improving or stable conditions
Why this matters at sea
A rapid fall in barometric pressure is one of the classic warning signs of an approaching depression or storm. Deck officers monitor pressure trends as part of weather observations.
Who is this for?
Useful for deck officers, cadets and anyone responsible for weather observation and voyage planning.
Important note
This tool gives a simple indication only. Always combine it with official weather forecasts, satellite data and company procedures.