12Z GFS Coldest Day of Winter Saturday in Northeast

Climate Impact Company Midday Update

Issued: Monday February 2, 2026

Highlight: Coldest day of winter Saturday in Northeast.

Fig. 1-2: The 12Z GFS projects the coldest day of winter in the Northeast U.S. this Saturday. Afternoon temperatures and wind chill are indicated.

Discussion: The coldest day of winter in the Northeast is projected for Saturday (Fig. 1-2). During the afternoon, the 12Z GFS indicates temperatures not reaching 10F in Boston while wind chill is routinely 10-15F below zero (during the afternoon). The Sunday morning low temperatures are near zero in Boston. The Boston heating degree day for Saturday is probably around 60 with an effective HDD of 70-75. The 12Z GFS identifies the frigid Northeast U.S. 6-10-day forecast while the remainder of the U.S. is warm (Fig. 3) followed by a warm-up into the East in the 11-15-day period (Fig. 4).

Fig. 3-4: The 12Z GFS U.S. medium range temperature anomaly forecast.

Table 1: The midday 12Z GFS U.S. gas population weight HDD projections into middle February.