Although the national capital is experiencing bright sunny days, the mercury has registered a sharp decline. The night temperatures plunged to 4.4 degrees from yesterday's 7.5. This is three degrees below normal. The day temperature also settled a notch below average at 20.1 degrees. The chilly winds which had made the days even cooler have however abated. Weatherman predicts mercury to rise marginally in the coming days. The Met department expects the sky to remain mainly clear and sunny today with the maximum and minimum temperatures likely to oscillate between 21 and seven degrees.