Early on the 2nd a tropopause polar vortex (TPV) was dislodged from its position over Hudson Bay. Over time temperatures within the TPV had become very cold, with mid level temperatures around -40 degrees Celsius. The ensuing cold front blasted across Ontario in 24 hours, reaching the North Country early on the 3rd. Temperatures fell throughout the day, with wind chills reaching -30 or colder by the afternoon for most locations. Wind chill warning criteria was met at many locations for 12 to 24 hours. Hundreds of warming shelters were opened during the event. While the cold air remained until the 5th, diminishing winds and temperatures climbing back above freezing allowed wind chills to warm above thresholds during the first half of the day on the 4th.  Most areas reported a top 3 coldest wind chill reading on record for this event.  Mount Washington Observatory reported the coldest ever wind chill reading since the observatory has been open with a reading of -108.4 degrees Fahrenheit.

Extreme Cold/Wind Chill in NORTHERN COOS, NEW HAMPSHIRE
From 03-FEB-23 13:00:00 to 04-FEB-23 11:00:00 (EST-5)
Reported by: Mesonet

By the morning on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -55 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in NORTHERN GRAFTON, NEW HAMPSHIRE
From 03-FEB-23 14:00:00 to 04-FEB-23 11:00:00 (EST-5)
Reported by: Mesonet

By the afternoon on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -55 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in SOUTHERN GRAFTON, NEW HAMPSHIRE
From 03-FEB-23 16:00:00 to 04-FEB-23 12:00:00 (EST-5)
Reported by: AWOS

By the afternoon on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -45 degrees early on the 4th before winds gradually began to diminish. This included -43 degrees at Plymouth Municipal Airport and -39 degrees at Lebanon Municipal Airport.

Extreme Cold/Wind Chill in NORTHERN CARROLL, NEW HAMPSHIRE
From 03-FEB-23 16:00:00 to 04-FEB-23 12:00:00 (EST-5)
Reported by: Mesonet

By the afternoon on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -45 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in SOUTHERN CARROLL, NEW HAMPSHIRE
From 03-FEB-23 16:00:00 to 04-FEB-23 11:00:00 (EST-5)
Reported by: Mesonet

By the afternoon on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -45 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in SULLIVAN, NEW HAMPSHIRE
From 03-FEB-23 18:00:00 to 04-FEB-23 11:00:00 (EST-5)
Reported by: Mesonet

By the early evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in BELKNAP, NEW HAMPSHIRE
From 03-FEB-23 18:00:00 to 04-FEB-23 10:00:00 (EST-5)
Reported by: AWOS

By the early evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish. This included -40 degrees at Laconia Municipal Airport.

Extreme Cold/Wind Chill in STRAFFORD, NEW HAMPSHIRE
From 03-FEB-23 18:00:00 to 04-FEB-23 09:00:00 (EST-5)
Reported by: ASOS

By the early evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish. This included -39 degrees at Skyhaven Airport.

Extreme Cold/Wind Chill in MERRIMACK, NEW HAMPSHIRE
From 03-FEB-23 19:00:00 to 04-FEB-23 11:00:00 (EST-5)
Reported by: ASOS

By the early evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish. This included -42 degrees at Concord Municipal Airport.

Extreme Cold/Wind Chill in CHESHIRE, NEW HAMPSHIRE
From 03-FEB-23 20:00:00 to 04-FEB-23 09:00:00 (EST-5)
Reported by: ASOS

By the evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish. This included -38 at Jaffrey Silver Ranch Airport and -38 at Dillant-Hopkins Airport.

Extreme Cold/Wind Chill in WESTERN AND CENTRAL HILLSBOROUGH, NEW HAMPSHIRE
From 03-FEB-23 20:00:00 to 04-FEB-23 09:00:00 (EST-5)
Reported by: Mesonet

By the evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in INTERIOR ROCKINGHAM, NEW HAMPSHIRE
From 03-FEB-23 20:00:00 to 04-FEB-23 09:00:00 (EST-5)
Reported by: Mesonet

By the evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish.

Extreme Cold/Wind Chill in EASTERN HILLSBOROUGH, NEW HAMPSHIRE
From 03-FEB-23 20:00:00 to 04-FEB-23 09:00:00 (EST-5)
Reported by: ASOS

By the evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish. This included -39 degrees at Manchester-Boston Regional Airport and -39 degrees at Nashua Boire Field.

Extreme Cold/Wind Chill in COASTAL ROCKINGHAM, NEW HAMPSHIRE
From 03-FEB-23 20:00:00 to 04-FEB-23 10:00:00 (EST-5)
Reported by: ASOS

By the evening on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -40 degrees early on the 4th before winds gradually began to diminish. This included -40 degrees at Portsmouth International Airport at Pease.

Extreme Cold/Wind Chill in SOUTHERN COOS, NEW HAMPSHIRE
From 03-FEB-23 13:00:00 to 04-FEB-23 11:00:00 (EST-5)
Reported by: ASOS

By the afternoon on the 3rd wind chills were reaching -30 degrees. Ambient air temperatures continued to fall into the double digits below zero with winds gusting in excess of 35 mph. The coldest wind chill values approached -55 degrees early on the 4th before winds gradually began to diminish. This included -45 degrees and Berlin Regional Airport and -49 degrees at Mount Washington Regional Airport.  Mount Washington Observatory reported the coldest ever wind chill reading since the observatory has been open with a reading of -108.4 degrees.