US natural gas futures extended gains to trade near $4 per million British thermal units, the highest since December 2018 on expectations of growing demand for air-conditioning amid forecasts for hotter than expected weather over the next two weeks. Natural gas futures have also been supported by strong demand for US exports of liquified natural gas as global gas continues to trade above US prices. Gas demand has been rising from China, Europe, Brazil, where droughts added to the competition by curtailing power output from hydroelectric dams, Canada and Pacific Northwest. Particularly in Europe, buyers on the continent have struggled to replenish tanks that are at the lowest for this time of year in a decade.