万(まん)一(ひと) manhito雨(あめ) ameが ga降(ふ)っ()た()ら() futtara旅(たび) tabiは wa楽(たの)し()く()な()い() tanoshikunaiだろう darou。 If it rains, the trip probably won't be any fun. travelweatherhypothetical situations~たら (conditional)万一 (if by chance)i-adjective negative (~くない)