Olive trees will stand down to minus 12 deg c when established (3 feet plus).
On the nursery my olive trees stay out all winter without being covered up.
Olive trees are incredibly easy to look after, requiring very little water when established in the ground. However regular watering is essential if you intend to keep your tree in container.
They are best positioned in a sunny spot if you would like them to produce fruit. Tomato feed is a good way of increasing the likelihood of your olive tree bearing fruit.