Montana records coldest temperature ever this early in the season in contiguous U.S.

The station in Potomac, Montana reported a temperature of -33 °C (-29 °F) on Sunday morning, October 25, 2020– the coldest ever temperature in the contiguous U.S. this early in the season, the National Weather Service (NWS) confirmed.

"It's official," said NWS Missoula.

"The coldest temperature this morning (October 25) in the contiguous United Staes occurred at Potomac, Montana."

At Townsend, the low of -20.5 °C (-5 °F) set a daily record and also broke the previous one set in 1901. Other cold temperatures recorded were -26.1 °C (-15 °F) at Sula, -25 °C (-13 °F) at Ronan and -23.9 °C (-11 °F) at Melville.

Hundreds of temperature and snow records were also observed from Texas to Montana after early-season winter storms hit parts of the northern U.S.

On the same day, NWS Marquette recorded 20.3 cm (8.3 inches) of snow, breaking the old record of 7.9 cm (3.1 inches) set in 1976. Holter Dam registered the most snow on the ground in Montana at 48 cm (19 inches).

"This recent snowfall also established a new monthly snowfall record for the month of October at our office."

On October 26, Butte registered -27.8 °C (-18 °F), the third earliest below zero reading and third coldest October temperature on record. It also broke the single-day record low for October 26 of -12.8 °C (9 °F) set in 2002.

During the same period, Kalispell registered -17.8 °C (-0 °F), breaking the single-day record low temperature for October 26 of -12.2 °C (10 °F) set in 2002. It also tied for the fourth coldest October low and marked the fifth earliest reading of zero or colder.

In Missoula, residents shivered through -20.5 °C (-5 °F), the second earliest below-zero reading and second coldest October temperature on record. 

The record snowfall and temperatures were caused by a deepening upper-level trough and a surge of cold Canadian air, according to NWS.

Featured image credit: NWS Missoula