Definition
Atmospheric phenomena, other than precipitation, that reduce horizontal visibility at or near the surface. Common examples include fog, mist, haze, smoke, dust, sand, volcanic ash, and blowing snow. Obstructions to visibility are reported in weather observations and broadcast in services like ATIS when they affect what a pilot can see along the runway and surrounding airspace.
Plain English
Things in the air, other than rain or snow falling, that make it harder to see — like fog, haze, smoke, or blowing dust.
Context Anchor
You may hear this on ATIS as part of the airport weather report, especially when the reported visibility is reduced.
Derivation
Obstruction' comes from the Latin obstruere, meaning 'to block up' or 'build against.' In this context, the air itself contains particles or droplets that block the pilot's line of sight, even though nothing solid is in the way.
Why Pilots Care
These conditions limit visual references for takeoff, landing, and VFR flight, often requiring instrument procedures instead.
Intuition Check
Do not read this as buildings, towers, trees, or other physical obstacles. In weather reporting, obstructions to visibility means things in the air that reduce how far you can see.
Example Sentence 1
ATIS reported visibility of two miles with mist and smoke listed as obstructions to visibility.
Example Sentence 2
The pilot checked the ATIS for obstructions to visibility before deciding on a visual approach.