Oamaru got 113mm of rain in August, which Niwa senior climate scientist Georgina Griffiths said was about three times the 37mm which normally fell during the month.
"For Oamaru, that's 307% of the August normal.
"Much of the east coast and coastal Otago area trebled normal rain amounts. Timaru had three and a-half times."
Ms Griffiths said the 156mm of rain in Timaru made it the third wettest August recorded there since 1881.
She added August was also notably warmer nationwide, with the average mean temperature of 7.8degC in Oamaru "well above average".
MetService media and communications meteorologist Daniel Corbett said although 113.2mm of rain was recorded in Oamaru in August, the 30 days preceding August 22 had been even wetter, with more than 150mm of rain recorded.
"The last two days of July had 40mm. For the whole month [of July] they had 49mm, so technically they had a month's rainfall in the last two days."
Although Mr Corbett said more showers were forecast for the town yesterday and today, the end of the week should be warm and dry.
"Wednesday is the day for the picnic baskets - [a predicted] 17degC with sunshine."
Farms across North Otago are drying out after the drenching, but are still in need of a prolonged warm spell to reap the benefits of extra pasture growth, brought on by the rain.
North Otago Federated Farmers president Richard Strowger said pasture growth had "certainly picked up" since it stopped raining around the last week of the month.
"The grass has been growing really well. It took a bit to dry off sufficiently so it wasn't waterlogged and it could start to grow.
"Soil temperature is still the biggest limiting factor at the moment - we really need the sun to come out, and some hot sunny days, so that grass can really start growing flat out."
PGG Wrightson livestock agent Glenn Hopkinson added that although the ground had not totally dried out yet, a prolonged sunny spell would allow the grass to "bolt.""All we need is a bit of sun."
Elsewhere in Otago, Dunedin also received more rain than normal, with the 103mm recorded 185% above normal.
Middlemarch got 25.4mm of rainfall in August , 121% of the August average of 21mm.
Raineffects hydrologist Dave Stewart said the 169.4mm of rain in Palmerston during the month, meant it was the third wettest August since records began.
Conversely, Queenstown enjoyed its sunniest August on record (170 hours) and Balclutha's residents worked on their winter tans during the town's second sunniest August on record (159 hours).