The Niwa weather station at Musselburgh showed the city had its equal-driest April since records began in 1918.
Just 12mm of rain fell in the city for the entire month.
Dunedin Airport also recorded 12mm, making it the Taieri’s third-driest April.
Niwa meteorologist Ben Noll said April was persistently dry, particularly in the east of both islands, due to regular bouts of westerly foehn winds.
The hot, dry winds on April 4 also helped Dunedin City set an April daily maximum air temperature record of 28.5degC — the highest April temperature since 1947.
On the same day, Oamaru posted a a record 27.5degC.
Mr Noll said above-average temperatures were common across the country during the month, but Otago was more than 1.2degC warmer than usual — "well above average".
"On April 4-5, numerous record and near-record temperatures occurred in the South Island, including a maximum temperature of 30.8degC in Timaru ... New Zealand’s fourth-highest April temperature on record.
"A ridge of high pressure was anchored to the north of the country while a strong low crossed to the south," he said.
"This pattern created a strong pressure gradient over the South Island, leading to the development of foehn northwest winds.
"The origin of the air mass could be traced back to the Pilbara region of Western Australia."
The lowest temperature in April was -6.4degC, observed at Lake Pukaki on April 28.
The highest wind gust of the month was at South West Cape (Stewart Island) on April 4, when wind speeds reached 178kmh.
It was an April record for the weather station and Gore also recorded its highest wind gust on the same day when the wind hit 117kmh.
