Olive trees themselves can cope with occasional temps down to -10. They're hardier than citrus. But whether they will produce fruit is another matter.

What do you mean about the fruit?

Olive trees are much hardier than citrus. To get fruit you need a two month period of temps below 10c but anything lower for a prolonged period can inhibit flowering later on, as does dryness. You also need hot summers. Many people successfully grow olive trees in the Southern and milder areas of the U.K. but very few manage to get fruit.

btw I was taking your mention of -10 to be Celsius.

Ok thanks. I’m having trouble curing the few olives I got, the taste is too intense yet.

I wouldn't plant a Mediterranean origin tree in anything described as a frost pocket. Tropical origin citrus seem even less suitable, most of those can only take comparatively light frosts.