They will not survive winter. I did the same, ended up with tonnes of guppies by fall. Placed a free ad, couldn't get rid of them all. One day I think it went to 8c, (water temp) and all remaining just went belly up.
Yeah, a really great way to control mosquitoes in the summer, but Coastal BC still has nights on end with freezing to slightly below freezing temps in the winter. The guy in the video with the slow said he put 2 aquarium heaters out there and raise the temperature quite a bit. I don't think it's a very good use of electricity personally, but hey, it you must have a pond, and it has to be subtropical/guppies, fill your boots