Owen, climate is changing....when we first moved to Nipomo local nurseries did not think we could grow avocados. We consistently had low 20's during the winter with long duration. Between freezing years I grew up different tender trees to the point of having some success. We used covers, return stack heaters (lots of diesel), and sprinklers. We therefore had limited success. Now, we see bare 28 degree winters rarely, short duration, don't see any frost damage. One year 45 yrs ago we had 17 degrees, killing many eucalyptus growing in the area. Our 40 varieties of avocados are mature, about 45 macadamias doing well, and white, yellow, black sapotes undamaged. Last year I planted out 6 mangos, put another 8 in the greenhouse. All will be out this Spring. I did encircle and cover the outside mangos for 2 nights last year. I will be planting out some other subtropicals this Spring also like Monkey Orange, Nance, and two lychees (Already have had Longans out for years). Don't know how cold you get in Atascadero, but life is short and planting out these "rare" fruits is a gamble. I'm more worried about our reduced rainfall. Then again, now maybe I've brought down the gods of the freezes as a result of the aforementioned.