Tauranga was pelted with two-and-a-half times more rain than usual last month making it the wettest July in more than 60 years.
Niwa figures show the 328mm of rainfall recorded at Tauranga Airport made it the second wettest July since records began 114 years ago.
Tauranga's soggiest July on record was in 1951 when 348mm of rain fell.
Te Puke was pounded with 382mm of rain, more than two times the average amount for the month, making it the wettest July since records began in 1973.
It was a month of two extremes, Niwa senior climate scientist Georgina Griffiths said: "The month started out really dry and really cold and ended up really wet and really warm."
About 85 per cent of the rain fell in the last two weeks of the month.
This means that despite the unusual amount of rain the daylight hours recorded in the Bay of Plenty were only just below usual.
The temperature last month was higher than usual with an average of 10.8C in Tauranga and 9.8C in Te Puke.
Heavy rainfall in the last half of the month caused slips and flooding around the region on a number of occasions.
The bill for the clean-up after Monday's deluge could cost two councils almost $50,000.
Western Bay of Plenty District Council transportation network manager Jim Paterson estimates it will cost about $20,000 for the council's role in the clean-up.
This includes tending to damaged trees and removing slip material from roads.
Tauranga City Council spokesman Marcel Currin said it was expected the city council's bill would come to about $27,000.
Road inspections and routine maintenance came to about $5000 while about $6000 had been spent on fixing damage to gravel walkways around the city.
About $1500 of tree work had already been done but the cost was expected to be between $8000 and $10,000 as uprooted trees are dealt with. Seawall repairs in Memorial and Fergusson parks came to $2000.
The cost of maintaining the stormwater network was not yet known but Mr Currin says it would cost about $4000 for the pre- and post-storm checks and clearing of known blockage points plus the expense of other callouts.
The New Zealand Transport Agency was not able to provide the Bay of Plenty Times with an estimate as the contractor had not yet finished assessing the cost of the repair works.
Bay of Plenty Regional Council duty flood manager Mark James says the Kaituna River reached its second warning level during the storm but caused no damage.
Metservice yesterday issued a severe weather warning for the Bay of Plenty predicting heavy falls in the ranges today and tomorrow.