You know this will be a future lock don't you ??
Nothing really wrong with a 10w or 15w in many many parts of this continental United States...
A 5w in my opinion is a good idea but certainly not a necessity even in my area... Of eastern Virginia... Coldest I have seen it... January 21, 1985 day after a good snowstorm and one of the biggest Arctic outbreaks in the last 40 years... got down to -12°F that am... The coldest I have witnessed since.... January 2017 where we got down to -7 in New Kent county.... Even in both cases a good 10w would still be all right.
Other areas north and west a 5w would be more advisable... Even in area west of Charlottesville it can be a good amount colder there even when it's cold where I am at... Same thing is true in Maryland... West of the Allegheny front it can be quite a bit colder than the areas east of that... Coldest temp here in Virginia was on that January 21, 1985 at a place I have driven up to... Mountain Lake.... -34°F... At 3,700 ft+ of elevation west of Blacksburg Va. Places like that or Burke's Garden in southwest Va can get extremely cold and much colder than areas just to the southeast of those locations. Like Roanoke can be 15-20 degrees warmer even in cold weather vs Mountain Lake or Burke's Garden... If I lived in beautiful Burke's Garden... I'd run a 0w just in case it got super cold... Burke's Garden by the way is amazing area to see... Surrounded by mountains on all sides... Farms with pastures and very nice homes dot the high elevation at 3,600 ft "valley" floor.