Autos are not a good choice for outdoor growing, they really do need 18/6 of light/dark to perform properly.
You are better off growing photoperiod fems outdoors and in 3 months you can harvest 10 times as much as from any auto outdoors.
Cold (soil) temps and limited daylight at this time of year will cause slow growth as well.
In my experience, if you must grow autos outdoors, planting seeds 4-5 weeks before the summer solstice seems to work best, as the days are the longest that they are ever going to be all year and the temps are far more favourable too.