Fear of thunder
An abnormal and persistent fear of thunder that causes undue anxiety even though sufferers realize that thunder itself poses no threat to them.
When outdoors during a thunderstorm, they may suffer excessive anxiety.
When indoors, they may hide under beds or desks, behind sofas, or in closets.
Fear of thunder is termed 'brontophobia,' a word derived from the Greek 'bronte' (thunder) and 'phobos' (fear).
'Brontophobia' has given us the English word 'brontometer,' an instrument for recording the activity of thunderstorms.
A related term: Astraphobia, fear of thunderstorms.