Distinguish North Sea approaches, Kattegat/Skagerrak, the Belts and Sound, and Baltic island passages.
Choose the waterway before choosing the forecast
Denmark connects North Sea approaches, Skagerrak, Kattegat, the Belts, Øresund and Baltic island routes. Those are distinct planning contexts, not interchangeable names for a single national forecast. A harbour-hopping itinerary can cross several forecast boundaries and busy shipping routes in one day. Write the actual strait and exposed connection into the plan, and avoid treating a Copenhagen town icon as weather for Bornholm or the west Jutland coast.
Use DMI's named marine sectors
DMI lists sector products for the Belts/Sound, western Baltic, Bornholm and neighbouring northern waters. Select each applicable area, then read the current issue and valid hours rather than relying on the index title. Some details are loaded dynamically; if the bulletin does not appear, obtain it through another official channel. Add a Swedish or German product where the actual track needs it, not simply because the destination has a Danish name.
Wind against current requires a timed check
Check current direction and strength for the intended transit hour, not the latest arrow on a map. DMI's current display is model evidence, not a measured stream at every narrow entrance. Compare the forecast wind and wave direction with that flow and the yacht's progress. Surface and deeper currents need not match. A modest national wind number can conceal a demanding strait segment, especially when the arrival timing cannot easily change.
Actual level and chart reference matter
The astronomical tide varies across Danish waters; the small tide in parts of the Baltic does not remove wind-driven high or low water. DMI level observations, model forecasts and official storm-surge warnings are different products. Record station, reference level and timestamp, then verify compatibility with charts and the selected harbour approach. This page does not supply under-keel clearance, a bridge-opening promise or an entrance-safety calculation.
Traffic, active notices and the alternative
Check active Danish nautical information for work areas, navigation and shooting notices separately from weather. In busy waters retain current charted route systems and COLREGs, and determine reporting obligations for the actual vessel rather than copying large-ship procedures. A waiting harbour or inside alternative must be accessible under the forecast direction and current rules. Finish with a new-bulletin time and an explicit trigger to delay, shorten or abandon the exposed leg.
Official products by task
- DMI named sea-area forecasts — Select Bornholm, western Baltic, Belts/Sound, Kattegat, Skagerrak or the applicable North Sea sector. Read the actual issue; sector pages may need JavaScript. This is not one forecast for all Danish waters.
- DMI water-level observations and forecasts — Choose a relevant gauge, observed versus forecast values and vertical reference. Automatic level curves are not identical to official storm-surge warnings or an entrance clearance.
- DMI current forecast — Model-current display; inspect depth, run and valid hour where provided. A surface grid arrow is not measured stream through a specific harbour or strait.
- DMI wave forecast — Model wave product for Danish waters. Match direction and valid time to the leg; an open-grid significant wave value does not describe harbour wake or breaking at a shallow entrance.
- Danish active nautical information — Official publication point for active notices, navigation and shooting warnings; responsibility is stated as Beredskabsstyrelsen/Sikre Farvande. Separate these messages from DMI weather forecasts.
Waters and onward passages
- Danish straits
Check wind, current and the transition between Baltic and North Sea areas.
- Skagerrak and Kattegat
Compare named sea areas with forecasts for the coastal approach and narrow straits.
- Baltic Sea
A Baltic overview should lead to the right national sea sector and water-level product.
- North Sea approaches
The North Sea needs national coastal products as well as the broader shipping-area forecast.
Departure ports and bases
- Copenhagen
Prepare the Sound crossing and the specific Copenhagen harbour approach separately; forecast current, construction notices and traffic can change the usable plan.
Prepare a passage brief
Bring route timings, vessel and crew profile together with checked sources and reassessment triggers. Personal AI analysis and expert review are in invitation-only closed testing. An editorial geographic page does not extend the calculation service’s actual coverage.