The olive requires rather warm temperature, light humidity, and absence
of heavy frosts. It can withstand temperatures of -7 to -8 degrees C. or
even lower if not too prolonged, and if the change to higher temperature
be gradual. Moist cold is more unfavorable than dry. The altitude at
which it will grow depends on the local climate. The climate of the
countries bordering on the Mediterranean and that of California are
particularly favorable.