February 03, 2023

Lowest Windchill in U.S. History

Mount Washington, New Hampshire is well known to most meteorologists. 

A mountain-top weather station there is famous for possessing the highest near-surface wind speed ever recorded in the U.S.:  231 mph.

But today, the Mount Washington Observatory has broken another record:  the lowest windchill temperature ever recorded in the U.S.

Reminder:  windchill temperature combines wind and temperature to provide a measure of how much heat you are losing when you are outside.  Lower windchill temperature means a faster loss of heat from your skin.

If there is no wind, temperature and windchill temperature are the same.  But as wind speed increases, the windchill temperature drops below the effective temperature, since wind increases the loss of heat from your skin.    

The previous U.S. windchill record was -100F observed at McGrath Alaska.  That record has now been replaced by -107F at Mount Washington today, the combination of a temperature of -46F and windspeed of 95 mph (see below)

Potentially, the windchill may decline even further during the next few hours.

Windchills below -98F are not even shown on the official National Weather Service windchill chart (below).  At a windchill below -100F, frostbite occurs on exposed skin with 1-3 minutes.

Taking a broader view, the current temperatures over the Northeast US are stunning, with teens over coastal Long Island to around -20F over NE New York.

Several daily records should be broken for record cold during the next day.

Coupled with powerful winds, the windchills across the Northeast range from -50F over Maine and -11F over coastal New England, to -20/-30F over upstate NY.  

The Northwest had a blustery day today, and some showers and typical temperatures are expected this weekend.  Yawn.


  1. C'mon now, Cliff. I know you're a gardener. Is there not anything interesting going on out there? Imbolc was just a couple of days ago. Some of us are focused on what is behind all those clouds. The sun returns and that's more than enough 'weather' for me right now.

  2. I believe the Mount Washington Observatory broke it's own record for lowest windchill temperature in the USA. The previous record was -102.59F on 1/16/2004. The ambient temperature at the time was -43.6F with sustained winds of 87.5mph. Also, the -46F ambient temperature at the observatory ties the record lowest February temperature for NH set at the same location on 2/15/1943 and is the lowest temperature observed in NH since January, 1968 (also at the same location).

  3. https://mesonet.agron.iastate.edu/sites/obhistory.php?network=NH_ASOS&station=MWN&year=2004&month=01&day=16

  4. Off topic. Cliff, you mentioned the dwindling Mt snowpack in the previous post are there any signs of a turn around in the model?, clearly this isn't a classic la Nina for the mountains.

  5. Hiking up Tuckerman’s Ravine while carrying a pair of skis and skiing back down was probably not advisable this weekend.

  6. Interesting that you don't mention elevation with Mt Washington being 6,000 feet higher than McGrath (but way further south). What are the highest sites with regularly reporting? Also, I think the highest wind chills I have experienced have be in urban canyons!

  7. More support for wavy jet stream hypothesis.: Wavier jet streams driven by zonally asymmetric surface thermal forcing
    Woosok Moon et. al. PHAS, September 12, 2022, 119 (38) e2200890119
    Co-author John Wettlaufer, A.M. Bateman Professor of Geophysics, Mathematics, and Physics at Yale

  8. I'm truly surprised that Cliff would call this a "record" when in fact the current wind chill formula was changed in November 2001. Yes, a "record." Barely 21 years old.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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