As with the other Canary Islands, Fuerteventura benefits from being considerably further south than mainland Spain and receiving the cooling effects of the Trade Winds bringing cooler summer air down from further north.
Consequently, Fuerteventura has very mild winters and summers that do not get as hot as parts of southern Spain.
Fuerteventura is also a dry island, not having any significantly high ground to cause much precipitation from the north westerly Trade Winds although there is a greater chance of some cloud on the north west side of the island. The summer months are almost totally dry with the very occasional shower from October through to March.
Occasionally in the summer, the cooling north easterly winds can be replaced by easterly winds coming from central Africa and the Sahara desert, resulting in hotter and drier air than usual.
Daily average temperatures for Fuerteventura
Source: World Climate