Nothing like a cold spell to boost the nation’s natural gas demand, and cost.

Forecasts now indicate this week’s outbreak will be stronger than anticipated, with Chicago seeing sub-zero readings. In New England, spot prices doubled, according to Con Edison Energy, reaching prices not seen since February 2015 and turning the region into the world’s priciest market.

Total gas consumption jumped 31 percent to 115.7 billion cubic feet on Tuesday from Friday. That’s the most ever for this time of year in PointLogic Energy data back to 2007. Not only have more homes converted to the fuel from oil in Connecticut through Maine, the region’s generators are more reliant on gas to produce electricity than anywhere else in the country.

“Gas prices for tomorrow are extremely volatile and high,” said John Borruso, director of natural gas trading at Con Edison Energy in Valhalla, New York. “This is truly a gas demand driven event because the temperatures are so cold and it’s still December. The market is set up in a certain way in December, it’s not prepared.”

Gas for next day delivery on Enbridge’s Algonquin city gate in New England, including Boston, recently traded at $25 per million British thermal units, more than double from trading Friday on the Intercontinental Exchange, Borruso said. Prices jumped to $30 on the nearby Kinder Morgan Inc.’s Tennessee Zone 6 system because of constraints on gas flows out of Canada, he said.

The broader gas market doesn’t seem worried that big jump in demand this week will create a supply crunch later in winter. Gas futures for January delivery fell 0.9 percent to settle Tuesday at $2.643 on the New York Mercantile Exchange, down 28 percent from a year ago.

“I’m not sure as it gets cold if prices will go higher,” he said. That’s because many Northeast generators have dual fuel capabilities and it may be cheaper to start burning oil instead. Fuel switching makes sense in New England when gas is around $14 per million btu and that drops to around $10.50 or $11 in New York, he said. “‘It’s going to be an interesting week.”