Growing olive oil trees requires a subtropical climate. The olive trees do great with mild winters and long, dry, and warm summers. It is challenging if not impossible to attempt to grow olive oil in tropical climate. They are very sensitive to freezing conditions that last days or hard freezing going below 15ºF (-10ºC). Such temperatures will kill the olive tree or damage it severely. Temperatures that go below 22ºF (-5ºC) will kill branches and small wood. Even if the trees were to survive the harsh climate, the flavor of the olive oil will be compromised.
Some notable locations with suitable climate for growing olive include California's coastal valleys and the Mediterranean region in Europe.
It is advisable to avoid growing in climates where there is a risk of frost especially during bloom (around late April to about mid-May) or in sites where freezing is likely to occur before harvest. Summer rain is capable of causing bacterial and fungal infections while extremely hot and windy conditions can also be dangerous as they will interfere with fruit set.
Olives still require some reasonably cold climate to facilitate proper flower development. The recommended temperatures should be below 45º F for 200 hours during winter and should not go below 22º F , according to guidelines by the University of California.
There are several factors that determine the level of cold tolerance that an olive tree can withstand, including the amount of water in the tree's tissues and temperature fluctuations.
Overall, a well drained site that receives sufficient regular water and a minimum of six hours of direct sun per day is ideal for growing olive oil trees. Ensure the site is well protected from any possible cold winds.
Once you conclude that the identified site has good climate, the next step is to select the right variety. Planting is best done during November-December for sites with mild climate. February-March is the best planting season for areas with colder conditions.