Temperatures soared to a sizzling 26degC on Saturday and 27degC yesterday.
Thousands of people spent most of the weekend beside the lakes or on the banks of the Clutha River, but no trouble was reported on the water.
Harbourmaster Marty Black estimated there were between 1600 and 2000 jet-boats and jet skis on Lake Wanaka on Saturday and a similar number yesterday.
Most of the warnings being issued were to people who were not wearing life jackets.
Just one fine was issued yesterday on the Clutha River for failing to wear a life jacket.
However, most people had a good attitude to water safety, he said.
Mr Black said Lake Wakatipu had been chaotic in Queenstown on New Year's Eve, where he was busy keeping boats away from the fireworks zone.
Wanaka's beach and street clean-up started early yesterday, with Downer EDI employee Debbie Meek, of Alexandra, among the dozens rising at 4.30am to get the job done.
"The beaches were full of pies, chips and beer bottles. That is the major litter I have found. But fireworks has also been a major one, because they all have these little caps. That's the tedious job. The rest of it can be done quite quickly," she said.
The only thing she had found of value was someone's bank card, which would be handed in to her employer, she said.
Wanaka residents Glen and Debbie McLachlan and their children Ben (8) and Ruby (6) were among the hundreds of families enjoying the relaxed and happy atmosphere at Roys Bay.
"We were here on Christmas Day and Boxing Day as well and we thought there were a lot of people then. There must be twice as many now," Mr McLachlan said.
Police were busy over the weekend dealing with minor disorder and traffic issues but were happy with the outcome.
Thousands of people partied in Wanaka's Ardmore St on Saturday night but police estimated the crowd was smaller than in previous years.
Constable Sean Hurley said four arrests were made on Saturday night for minor disorder offences.
Of more than 1000 people breath-tested around the district on Saturday night, just one driver was processed for being over the limit, he said.
Two men were processed for drink-driving on Friday night.
The one-lane Albert Town bridge was, as predicted by the New Zealand Transport Agency, a traffic congestion hot spot, with at least two minor accidents reported there over the weekend.
