Arosa has an average of 147 days of rain per year and on average receives 1,335 mm (52.6 in) of precipitation. The wettest month is August, with an average of 159 mm (6.3 in) of precipitation and an average of 14.5 days with rain. The month with the most days of precipitation is June, with 15.6, but with only 147 mm (5.8 in) of precipitation. The driest month of the year is February with 75 mm (3.0 in) of precipitation over 14.5 days
