How should you interpret ceiling and visibility in weather reports for flight planning, and what do they indicate?

• A. Visibility indicates cloud height.
• B. Ceiling is height of cloud bases; visibility is extent of sight distance; affects VFR vs IFR planning.
• C. Ceiling indicates wind speed.
• D. Ceiling and visibility are not used together.

Answer: (B)

The idea is that ceiling and visibility together tell you if you can fly by visual references or if you’ll be flying on instruments. The ceiling is the height of the base of the lowest cloud layer; in other words, it tells you how high the clouds are starting from the ground. Visibility is how far you can see horizontally. When planning, you look at both numbers because you need enough sky clearance (not too much cloud cover) and enough sight distance to see the ground, obstacles, and other aircraft.

If the ceiling is high and visibility is good, you can typically plan a flight under visual rules. If the ceiling is low or visibility is poor, you’d be pushed toward or required to fly under instrument rules. It’s also possible to have a high ceiling but limited visibility, or vice versa, and each scenario affects whether VFR is feasible. Weather reports compile these two indicators precisely so you can decide the appropriate flight plan and route.