Everyday skies · species
Cirrus uncinus
Hooks across the blue
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Full credit
Own work
Displayed at reduced resolution. See the original file for full licensing information.
Full credit
Own work
Displayed at reduced resolution. See the original file for full licensing information.
Full credit
Own work
Displayed at reduced resolution. See the original file for full licensing information.
Swipe or scroll sideways to explore the photographs. Photos may include other cloud types; names and credits come from their source records.
Spot it
Thin cirrus strands with a hooked or tufted end.
How it forms
Falling ice and differing winds shape curved streaks.
Read the sky
These patterns show conditions high above; do not time rain from a single hook.
Where to look
Look among upper-level cirrus fields.
Little sky facts
Reveal fact 1
Uncinus is a species of cirrus.
Reveal fact 2
The hooked end is a key identifying clue.
Reveal fact 3
Its strands consist of ice crystals.
Reveal fact 4
Rows of hooks can give the sky a combed appearance.
Try this
Turn one hook into a question mark.
Draw your own cloud ↗Read a little deeper
Met Office · formation and weather
Conditions described here are places to look, not a global frequency ranking. Use local weather forecasts and warnings for decisions. Never look directly at the Sun.