Definition
A long-range weather forecast based on the average weather conditions recorded for a specific location over many years, rather than on the current state of the atmosphere. It predicts what weather is typically expected at a given place during a given period, based on historical climate data.
Plain English
A weather prediction made by looking at what the weather has usually done at that place at that time of year, instead of looking at what the weather is doing right now.
Context Anchor
Seen in aviation weather discussions when planning beyond the range of normal short-term forecasts, or when considering seasonal weather patterns for a route or airport.
Derivation
From 'climatology' -- the study of climate, which is the average pattern of weather over long periods. The word climate comes from the Greek 'klima,' meaning region or zone. A climatological forecast leans on those long-term averages rather than today's atmosphere.
Why Pilots Care
Provides usable planning data for remote routes or seasonal operations where real-time observations do not yet exist.
Grounding Statement
A climatological forecast tells you what the weather is typically likely to do there, not exactly what it is doing right now.
Intuition Check
A climatological forecast is not the same as a current weather forecast. It is based on long-term patterns and averages, so it is useful for general planning but not enough by itself for a go/no-go flight decision.
Example Sentence 1
When planning a summer flying trip across the Rockies months in advance, the pilot consulted a climatological forecast to get a sense of the typical weather she could expect.
Example Sentence 2
For the winter ferry flight, the crew reviewed the climatological forecast to anticipate average cloud ceilings and icing risk.