What is your cut off temperature for not walking a short hair dog?

I have three dogs, two are triple coated long hairs so I use -15 to -20 as a cut off for not walking them. We have a two year old short hair that we rescued this year, if it was up to her she’d be outside 24/7 regardless of temperature! What do you use as a cut off point for not walking short hair dogs? It seems like opinions vary online so I thought I’d check with my fellow Edmontonians!