By one, tiny degree, students in McGrath – a small community on the upper Kuskokwim River in Interior Alaska – missed getting a day off from school on Tuesday.

It was 49-degrees-below zero. The school cut-off for weather days is 50 degrees-below. Sadly for the kids, it didn’t hit 51-below until they were in their classrooms for the day.

These are close to other worldly temperatures. The average temperature on Mars is minus-81 degrees – only 30 degrees colder, according to the National Aeronautics and Space Administration.  (NASA)

The temperature in McGrath on Tuesday was about four times closer to the temperature on Mars than to the temperature in Los Angeles where it hit 68 degrees at midday.  

Forty-five-degrees-below-zero is the safety limit set by the federal Occupational Health and Safety Administration (OSHA). Below that temperature, the federal agency says, all non-emergency outdoor work should stop.

The rules were written for the Lower 48 states. Alaskans are tougher.

Jennifer Vanderpool, a mother in McGrath, was pretty nonchalant about sending her kids off to school at 49 below.

“I dressed them in many layers and rolled them out of the (McGrath) hotel, off to school,” she messaged. “My 11 year old is quite offended and disinterested in my ‘when I was your age’ stories.”

Vanderpool grew up in McGrath in the bad old days before global warming when minus-40 and minus-50 sometimes just seemed to be the norm. She now manages the Hotel McGrath where you can still get a shiveringly good taste of the real Alaska this time of year.

David Cornberg, a young man featured 40 years ago in author John McPhee’s iconic “Coming Into the Country,” put the Alaska weather nicely in perspective on Tuesday.

The Interior city of Fairbanks and Los Angeles, Calif., were incorporated only about 50 years apart he noted, the latter at the very start of the 20th century and the former midway through the 19th century. But their growth patterns have proven dramatically different.

The Greater Los Angeles Area, where the skies are often sunny and the weather balmy, today boasts a population of 18.7 million people.  The Fairbanks North Star Borough, which covers an area nearly the size of New Jersey that turns into a frozen winter outpost, is home to fewer than 100,000. 

“I look at that, and I say ‘nature talks,'” said Cornberg, now 72 years old. People don’t live in 50-degree-below zero temperatures;  he said, they survive in 50-degree-below-zero temperatures.

Vanderpool put it even more simply:

“Minus-50 hurts.”

She meant it more than figuratively.

There’s hardly an Alaskan alive who has spent much time outdoors at those temperatures who hasn’t suffered some frostbite. And it wasn’t just minus-51 in McGrath on Tuesday; it was minus-71 with the wind chill.

At these sort of temperatures, the National Weather Service warns that exposed flesh can freeze in a matter of minutes. It is good weather for staying inside around a fire.

The goods news for most Alaskans, who cluster in the greater Anchorage area at the head of Cook Inlet near the Gulf of Alaska coast, was that it wasn’t expected to get anywhere near that cold in the state’s largest city.

The forecast there called for temperatures to bottom out at 15- to 25-degrees below zero.  Just to the north in the bedroom communities of the Matanuska-Susitna Borough, Tuesday night temperatures were already psuhing down near 30-below-zero.

It was a little unusual for the region in recent time, and a little shocking for residents coming off a more-than-year-long run of monthly temperatures above normal in a place where the climate has seemed for years to be steadily moderating in winter.

Now frigid Anchorage hasn’t seen a winter day colder than 15-degrees below since January 2012.