Temperatures will be tumbling to the single digits later this week in the five boroughs. This is our second cold blast this month, and this one will be colder and longer. Here’s what you need to know.

It's winter. Isn't it supposed to be cold?

Yes! January is the coldest month of the year for us, but the normal high this time of year is 39 and the normal low is 27. On Thursday, we'll have highs in the teens and lows near 5. That's more than 30 degrees below the normal.

Is this the polar vortex?

Yes and no. The polar vortex will be moving over Chicago, and air temperatures there could go to -20. For NYC, the polar vortex will miss New York City to the north and west, but it will still be close enough to bring us the deep freeze.

Just how cold will it get in NYC?

We’re expecting temperatures to drop to near 5 degrees on Thursday morning. The wind chill then will be between -10 and -20.

Is it safe to go outside?

Of course! Just be prepared. Frostbite can occur in as little as 30 minutes in these conditions, so be sure to cover your hands and head.

What about climate change?

A few very cold days isn't climate. Climate change (what we used to call global warming) is weather trends over decades, not days. For example, seven of the warmest winters for NYC have happened since 1995, while the last winter to rank in the top 10 coldest was 1977.

What's a NY1 Weather on the Ones insider tip for beating the cold?

Erick Adame: Don't be afraid to forgo fashion. Put on that clunky heavy coat and be ready for "hat hair."

John Davitt: Drink warm beverages. "Warm from the inside." Hot chocolate is my favorite.

Stacy-Ann Gooden: Dress in layers and keep your hands, feet and head covered. Don’t forget to keep a close eye on kids, pets and the elderly too.