Definition
The state of the atmosphere at a given time and place, described by variables such as temperature, pressure, humidity, wind, visibility, cloud cover, and precipitation. In aviation, weather refers specifically to those atmospheric conditions that affect flight planning, aircraft performance, and flight safety.
Plain English
What the air is doing right now and what it is expected to do — how warm or cold it is, how the wind is blowing, how clear or cloudy the sky is, and whether rain, snow, or storms are present.
Context Anchor
Pilots encounter this term in preflight planning, cockpit decision-making, instrument flying, and any discussion of whether conditions are safe or legal for a flight.
Derivation
From Old English 'weder', meaning air, sky, or storm. The word has always referred to the changeable condition of the atmosphere — which is exactly its aviation meaning today.
Why Pilots Care
Weather conditions directly determine whether a flight can be conducted safely and legally, and they remain the most common factor in weather-related accidents.
Intuition Check
Weather does not only mean storms or bad conditions. In aviation, weather means all flight-related air and sky conditions, including clear skies, wind, clouds, and visibility.
Example Sentence 1
The pilot checked the weather along the route before departure and found that low clouds would require an instrument approach at the destination.
Example Sentence 2
Changing weather along the route forced the pilot to divert to an alternate airport.