Natural gas climbed to its highest price in almost 17 months today on speculation that a cold start to spring will buoy demand for the heating fuel.Gas rose as much as 2.4 percent as MDA Weather Services predicted that below-normal temperatures will linger in most of the lower 48 states through April 1. The futures have rallied 25 percent from a one-month low on Feb. 15 as unusually cold weather and an increase in gas-fired electricity plants helped reduce a stockpile glut."It doesn't look like this rally is done yet," said Gene McGillian, an analyst and broker at Tradition Energy in Stamford, Conn. "The next two weeks, they're calling for below-normal temperatures. In this push-up to $4, we have basically seen a lot of shorts run out of the market."Gas for April delivery jumped 7.4 cents, or 1.9 percent, to $3.95 per million British thermal units at mid-morning on the New York Mercantile Exchange after rising to $3.96, the highest intraday price since Oct. 31, 2011. Trading volume was more than double the 100-day average for the time of day. The futures, which have climbed 18 percent this year, last traded at $4 in September 2011.Hedge funds boosted bets on U.S. natural gas to the highest level on record amid forecasts of colder-than-normal March weather that would stoke demand for the heating fuel, according to the Commodity Futures Trading Commission's March 15 Commitments of Traders report."Colder-than-normal March temperatures mean the 2012/2013 winter will likely end up close to normal, despite the mild weather in December," Goldman Sachs analysts led by Johan Spetz said in a note to clients.This amplified the tightening of the supply-and-demand balance that began last April, he said."We see increased upside risk to our price forecasts of $3.75 per million Btu for the second and third quarters of 2013 and $4.25 per million Btu for 2014," he said.The low temperature in Chicago on March 20 may be 16 degrees Fahrenheit (minus 9 Celsius), 16 degrees lower than the usual reading, according to AccuWeather Inc. New York's low on April 1 may be 31 degrees, 9 below normal.About 50 percent of U.S. households use gas for heating, according to the Energy Information Administration. Gas demand typically slumps between the peak heating-demand season and before hot weather drives power demand to run air conditioners.