The winter of 2023-2024 is likely to go down as the warmest on record for the United States. That goes a long way toward explaining why natural gas demand and prices deflated over the course of the heating season.

Ahead of an official call later this month by the National Oceanic and Atmospheric Administration (NOAA), AccuWeather said this week that its preliminary data showed the average temperature across the country would rank this winter as the mildest in records that date to 1893. The data span December, January and February – the heart of the season.

AccuWeather meteorologist Paul Pastelok said a strong El Niño pattern, which developed last summer, contributed substantially to a mild, mostly snowless winter season for the northern Plains, Midwest and Great Lakes –...