Pooches: How Cold is Too Cold for Dogs?

Here in Chicago we've gotten by with an extremely mild winter; we've even had less snow than Dallas! So this week's subzero temperatures have hit us all hard.
I think a lot of Chicagoans have learned to do it right because we are out there along with our pups on our daily walks. And we've gotten a lot of tips from our SociaBulls group.
Here are some things we've learned about keeping our pups extra warm:

Layers:

We have been noticing how all the urban Chicago teenagers 'layer up' with cold weather, so we've done the same thing with our pooches. We've been layering their hoodies under their coats. We even have some urban puffy coats we just received from RC Pet Products. The pooches are wearing the Skyline Puffy Vest. We like how the hoodies cover the under-area the coats don't reach.

Covering Up:

We like covering up the pooches' bare neck area with snoods. I don't know how much of a difference it does make, but it seems like the metal tags and parts of their collar can get very cold against their necks. Plus, the snoods do cheer us up on these dreary winter days.
Our pooches have colored fleece snoods (also shown here) from Sirius Republic.
And we have knit snoods--that make them look like animals--from Snug-A-Bull.

Dog Footwear:

We get a lot of questions about what we use to keep our pups' feet warm. In our experiences we haven't had to put on boots because their feet get cold on the pavement, but we do use boots when they are walking on snow-covered sidewalks. Snow will begin collecting on their feet, sometimes becoming ice-like between their toes. They also find the salt scattered on the sidewalks to be painful. We have tried using doggie boots, but it was too difficult for our pooches to keep on, so we just went with the PAWs disposable reusable boots.  We also like these boots for the muddy spring thaw walks when unmentionables start melting out from the snow. We wrote more about our quest for the perfect dog boot, here. 

We also heard a good question about knowing when your dog has had enough of the cold and when you know whether it's time to bring them back in.
For us, our pups will cut the walks short on their own and start pulling in the direction of home.
How does your pooch tell you when they're too cold?

Also:
Miss M and Mr. B do the dog-boot dance
What to do inside when it's too cold outside
What we hope was only once in a lifetime.