The national capital recorded its highest 24-hour December rainfall since 1997 on Friday, MeT officials said.The Safdarjung Observatory, figures of which are considered official for the city, recorded 33.5 mm rainfall, the second highest after 70 mm in December 1997, till 5:30 pm.The Safdarjung Observatory, figures of which are considered official for the city, recorded 33.5 mm rainfall, the second highest after 70 mm in December 1997, till 5:30 pm.