What is the meaning of the expression “rain or shine”?

rain or shine Rain or shine definition: regardless of the weather or circumstances; in any event See examples of RAIN OR SHINE used in a sentence

Rain or shine is a Gloucester based professional theatre company which specialises in outdoor summer tours of classical theatre to castles, stately homes rain or shine Rain or Shine Elastomeric Waterproofing paint is a self-priming water-based waterproofing paint for exterior and interior concrete surfaces