The Bay of Plenty region with 1403 sunshine hours, was also the third sunniest region for June behind Nelson (1446 hours) and Marlborough (1429 hours).
In the report, Niwa's principal scientist Chris Brandolino said June's rainfall was below or well below average across much of the country, including for all main centres.
Tauranga's 52mm of rain was "well below normal" for this time of year, he said.
Brandolino said higher than normal mean sea level pressure last month resulted in more southwesterly winds than usual over the country.
"Frequent rounds of high pressure late in the month contributed to unusually dry conditions and several rounds of colder than average morning temperatures," he said.
"With recurring high-pressure systems, there were fewer significant weather events during the month."
Metservice meteorologist Philippa Murdoch said the next few days there would be unsettled weather across Tauranga and the Bay of Plenty due to a series of active fronts.
Murdoch said the first was moving in an easterly direction overnight and was expected to bring some rain in the early hours today , followed by a more active front on Friday.
It could bring up to 20m of rain mostly during Friday afternoon, and on Saturday the weather was expected to be more settled in Tauranga but partly cloudy, she said.
Murdoch said another active front was due to move across the Bay of Plenty on Sunday, bringing more rain to Tauranga then easing to the odd shower by the evening.
The amount of rain on Sunday depended on how the active front tracked across the region, she said.
