Forecasts
What Is a Small Craft Warning? UK Strong Wind Warnings
Published · Last checked October 2026
In the UK, a 'small craft warning' is officially called a strong wind warning. The Met Office issues it for inshore waters (up to 12 miles offshore) when winds of force 6 or more are expected, typically between Easter and the end of September. In the USA, a small craft advisory is a similar alert, with thresholds that vary by region but usually start around 20 to 33 knots.
The UK strong wind warning
Leisure sailors in the UK often call it a small craft warning, but the Met Office term is strong wind warning. It is issued for the inshore waters forecast areas, which run around the UK coast out to 12 nautical miles, when mean wind of force 6 (22 to 27 knots) or more is expected.
The service runs through the main boating season, typically from the Easter holiday until the end of September, and at other times in some areas. Outside that period, rely on the inshore waters forecast itself and on gale warnings.
Why force 6 matters for small boats
Force 6 is the 'yachtsman's gale'. Large waves start to form, white crests are everywhere and spray becomes likely. A well-crewed cruising yacht with reefs in can cope, but dinghies, small open boats, kayaks and inexperienced crews can quickly get into trouble. It is also the point at which wind against tide in tidal races and headlands can turn genuinely dangerous.
| UK strong wind warning | US small craft advisory | |
|---|---|---|
| Issued by | Met Office | National Weather Service |
| Area | Inshore waters to 12 miles | Coastal and some inland waters |
| Threshold | Force 6 or more | Varies by region, often 20 to 33 knots or hazardous seas |
| Season | Typically Easter to September | Year-round |
| Next level up | Gale warning, force 8 | Gale warning, 34 knots |
How to receive it
- HM Coastguard maritime safety information broadcasts on VHF, announced on channel 16.
- The inshore waters forecast on BBC Radio 4 and the Met Office website.
- Navtex in your coverage area.
- Marina and harbour office notice boards, which often post the latest warnings.
What to do
Treat a strong wind warning as a planning trigger, not a ban. Ask whether your boat and crew can handle force 6 or more on the intended route, including the gusts and any wind-over-tide stretches. If you go, reef before you leave the harbour, shorten the plan and keep a bolt-hole in mind.
- Check timing: is the wind forecast during your passage or after you will be in?
- Check direction against the tide and the shelter on your route.
- Reef early and brief the crew.
- Have a plan B harbour, and turn back if it is worse than forecast.
See when is it too windy to sail and the weather awareness lesson for help deciding.