Gets down to 40 degrees need strain..

Im looking for a strain which can handle 40 degree weather for about 7-14 random days...im growing out in the mountains below the 45 parallel. I've read some literature, but Im looking more for advice from people who have grown outdoors in cold climates. As it stands, im going with lowryder #2 AK47, but if someone has any further knowledge or advice to make this grow successful, please drop a line.

I think most all pot could.

I'd get something with the potential to be purple, though, just for aesthetics. I'm sure those temps will really bring it out.