Not affected by climatic conditions; capable of normal operation regardless of precipitation, wind, sun, etc. / (figuratively) Always there when needed, reliable, dependable, loyal, faithful.

Alternative form of in all weathers

(UK) Whatever the weather is.

(automotive, American spelling, Canadian spelling) A tire with rubber that remains soft in below-freezing conditions, but gives longer tread life in warm conditions than winter tires

(automotive, British spelling, Irish, South African, Australian and NZ spelling) A tyre with rubber that remains soft in below-freezing conditions, but gives longer tread life in warm conditions than winter tyres