What information must always be included in a float plan concerning weather?

The correct choice for the float plan concerning weather is the inclusion of current weather conditions. Current weather conditions provide essential real-time information that can significantly influence safety and decision-making while engaging in water activities. These conditions include factors such as wind speed and direction, visibility, temperature, and the presence of storms or precipitation. Knowing the current weather helps occupants of the vessel to assess their immediate environment and plan appropriately.

Including a forecast for the next week would be less relevant since a float plan generally covers the immediate duration of the outing rather than extended projections. Historical weather data does not aid in current decision-making or planning because it reflects past conditions rather than present ones, making it irrelevant for immediate safety. Atmospheric pressure readings can provide useful information in some contexts, but they do not convey the comprehensive and immediate context needed for safety on the water that current weather conditions do.