The average annual rainfall increases from east to west , and it ranges from 700 to 1600 annual millimetres ( 27.6-63 in ) on average , reaching 6,300 millimetres ( 250 in ) on Mount Pico , the highest Portuguese mountain at 2,351 m ( 7,713 ft ) .
The average annual rainfall increases from east to west , and it ranges from 700 to 1600 annual millimetres ( 27.6-63 in ) on average , reaching 6,300 millimetres ( 250 in ) on Mount Pico .