it wouldn't be your cold days but your hot days that would be of concern. a quick google search points the pears are hardy for zones 5-9 with some varieties tolerating zone 4. but you are in zone 11 and the heat may be what ruins your plans. perhaps situating the tree in an area that just gets morning and evening sun avoiding direct afternoon sun would be enough to allow the tree to condition itself to zone 11.
oddly enough the asian pear came up in another google search i was doing this morning, i just found out i suffer from black cherry aphids....no shit.... who would figure such a thing existed? i was inspecting my evans cherry tree that is new for this year and i noticed these little black dots on the plant, what the ! on further inspection they covered the tree and they weren't there 2 days ago. so after squishing all of them, i ventured to find out what they were and sure enough, black cherry aphid. now i have other cherry trees, choke cherry and nanking cherry and they have never had bugs but apparently dark sour cherries have an aphid all to themselves!!!! and that's where the asian pear came into my search, apparent the black cherry aphid has a cousin that loves asian pears.... go figure!
good luck, plan accordingly and i am sure you will do fine.
