Lol, that's what sucks about living on the coast! I used to live near the atlantic coastline in Canada and the outside temps got as far as -45*C! A good idea for glass tanks is to build your own wooden lids that has a light fixture built into it. Make sure you screw in holes and put screen over them for ventilation. I wish I had a pic to show you, but all of my lids like that are in Canada. This works awesome for keeping the heat in on those cold nights! Good luck. 
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-Britney
Atlantic Reptiles(In the works)
2.4.1 Leopard Geckos: Ron, Raine, Dream, Tango, Go-Go, Johnneh and Salleh.
0.0.1 Lined Snake: Monty(Released back into the wild!)
0.0.1 Bearded Dragon: No name yet, lol.