Definition
The time delay between when weather data is observed or measured and when the resulting weather product is delivered to the cockpit display. Product latency means the picture a pilot sees on the display is always older than the current weather, sometimes by several minutes or more, depending on the product and the data link.
Plain English
The weather you see on your screen is not happening right now. It is a delayed picture of weather that was observed some minutes ago, processed, and then sent to the aircraft.
Context Anchor
Seen when checking the age and usefulness of aviation weather products before or during a flight.
Derivation
Latency comes from the Latin latens, meaning 'hidden' or 'lying concealed.' In modern usage it refers to the hidden delay between an event and its appearance — here, between the actual weather and the version of it shown to the pilot.
Why Pilots Care
High latency means conditions may have changed, so pilots must decide whether the data is still reliable for route and altitude choices.
Grounding Statement
What you see on the weather display already happened — sometimes 5, 10, or even 20 minutes ago.
Intuition Check
Do not assume product latency means the product is expired. It means there is a built-in time delay between when the weather information was observed or made and when you can use it.
Example Sentence 1
Because of product latency, the pilot stayed at least 20 miles from any displayed thunderstorm cell rather than threading between them.
Example Sentence 2
Because of product latency in the surface analysis, the pilot cross-checked current METARs to confirm the frontal passage had already occurred.