Rotorua's hottest day was February 3 at 30.2C, however, this was far behind the city's record of 35.1C set in 1940.
Tauranga's coldest day was 1.3C on July 10 while Rotorua dipped down to -2.3C on August 17.
Rotorua and Tauranga's mean temperatures were both higher than the average over the past 29 years.
Tauranga's mean temperature since 1981 was 15.2C, however, this year's mean temperature reached 15.8C.
Rotorua's mean temperature over the same time period was 12.8C, compared to the mean temperature this year of 13.3C.
Rainfall in both centres was significantly lower than historically, with Tauranga's 775.8mm close to 450mm below than average.
Rotorua soils received 1056.8mm of rainfall, less than the historical average of 1350mm.
Metservice meteorologist Lewis Ferris said 2020 had been "one of the warmest years on record across the globe".
Looking ahead, colder and wetter weather was forecast for the first few days of the New Year and people should keep La Nina in mind for the remainder of the summer months.
He said, "while it doesn't guarantee heavy rain approaching from the north it does increase the likelihood".
MetService would be alerting the people if anything serious was approaching, he said.
Federated Farmers Bay of Plenty president Darryl Jensen said the first six months of 2020 were "extremely tough" on farmers.
A dry spell that lasted through January, February and March set farmers up for a bad autumn, however, they were blessed with a "mild winter" with decent rainfall that pulled them through, he said.
This flowed into a "very good spring" with conditions allowing for smooth lambing and calving seasons and crop growth, he said.
This summer had been "typical" with a bit of rain here and there, however, he said the dry patch earlier in the year was still rearing its head with flow-on effects.
He said streams and water resources were low and farmers were "far from out of the woods".
"It's all up to the weather gods."
A number of farmers had told him that although they never normally stayed up until midnight on New Year's Eve, they did this year "just to make sure 2020 finished," he said with a laugh.
Waikato University Professor Karin Bryan, who specialises in environmental science, said extreme weather events, including temperature spikes, were expected to become more frequent.
She said research had shown that the impact of Earth warming was already affecting the country's marine life.
A recent study had shown there had been a bad case of cockle dieback in Leigh, which was a result of warm temperatures seeing them "cooking" in the water.
She said marine organisms were "sensitive to changing temperatures" and this could have detrimental effects on marine life in its entirety as species at the base of the food chain were first affected.
"We are working very hard to make sure our waters are in a robust ecological state to handle the ongoing impacts."
Brian Holden, a member of the New Zealand Meteorological Society, who had recorded weather in Rotorua for 30 years said climate change remained a "serious issue" and it was something he was consistently being made aware of from his daily recordings.
He said that 2020 had been a "varied year" and he had not recalled extreme frosts or other weather events like he had previous years.
His data showed Rotorua had seen 28 frosts throughout the year.
