The national capital today experienced its coldest day of the season so far with the mercury dipping to 6.6 degrees Celsius, a notch below the season's average. <br/><br/>According to a senior railway official, moderate foggy conditions were witnessed in the morning which resulted in delay of 40 trains.<br/><br/>The weatherman has forecast mainly clear skies for tomorrow with the likelihood of some mist and shallow fog. Maximum and minimum temperatures are expected to be around 23 and 9 degrees Celsius.<br/>' <br/><br/>