Darwin recorded its heaviest April rainfall in 13 years overnight, helping the city edge closer to its once distant wet season average. Rain and storms soaked the Northern Territory's capital from about 6pm last night, delivering 90mm by 8am this morning. Most of the rain fell in the first four hours, although the heaviest burst came at 8pm when 23mm poured in just half an hour. The deluge was caused by a low pressure system located to the west of Darwin within the monsoon trough. The low directed moist and unstable air over the western Top End, targeting Darwin with thundery rain. Falls this heavy in April have only occurred in Darwin five times during the past 70 years. There has now been over 90mm in just the first two days of April, more than 90 percent of the monthly average. However, this damp end may not be enough to help the wet season live up to its name this year. Up until the end of March, Darwin had only seen 82 percent of the usual wet season's rainfall, making it the driest for that period in eight years. This was a result of below average rainfall between October and January, thanks to a relatively inactive monsoon. More recently, increased monsoon activity over the Top End has produced above average rainfall during February and March, with this trend now continuing into April. Last night's soaking was the heaviest for April since 2000 and brings the month's running total to 91mm after just two days. The wet season's total has now reached 1,380mm, which is 87 percent of the long term average. Last night's rain improves Darwin's chance of reaching this average by the end of the wet season, although there is still a way to go. Darwin's wet season runs from October to April and typically produces 1585.4mm of rainfall. Darwin needs to record 295.2mm during the month April to reach the long term average. Visit http://www.weatherzone.com.au/station.jsp?lt=site&lc=14015&list=ds to see how Darwin is tracking throughout the month.