The saffron crocus thrives in climates similar to that of the Mediterranean maquis or the North American chaparral, where hot, dry summer breezes blow across arid and semi-arid lands. Nevertheless, the plant can tolerate cold winters, surviving frosts as cold as −10C (14F) and short periods of snow cover.
Tasmania has proved to have ideal conditions for growing the highest quality of saffron, and it is now renowned worldwide as one of the premiere locations for saffron production. Indeed many other states in Australia also produce saffron, as well as some areas of New Zealand.
However, if not grown in wet environments such as Kashmir (where rainfall averages 1,000–1,500mm annually), irrigation is needed—this is true in the saffron-growing regions of Greece (500mm of rainfall annually) and Spain (400mm). Rainfall timing is also key: generous spring rains followed by relatively dry summers are optimal.
Rainfall immediately prior to flowering also boosts saffron yields. However, rainy or cold weather occurring during flowering promotes disease, thereby reducing yields. Persistently damp and hot conditions also harm yields, as do the digging actions of rabbits, rats, and birds.