A northwesterly wind coming from over the mountains meant Dunedin experienced an unseasonable high of 24degC yesterday.
MetService meteorologist Emma Blades said the warm temperatures were ''certainly unusual'' for this time of the year - the average temperature for Dunedin in May is 14degC.
Dunedin also hit 24degC last year in May in what was ''probably a similar tropical wind'', Ms Blades said.
Central Otago had reasonably high temperatures in the late teens and early 20s yesterday, but was colder than Dunedin because of more cloud cover in the afternoon, Ms Blades said.
Gore hit 20degC, while Queenstown and Alexandra got to 15degC and 17degC, respectively. The high in Oamaru was 23degC, but the national high was in Kaikoura, where it was 28degC.
Ms Blades said the wind which caused the high temperatures along the east coast is known as a foehn - a moist wind which dumps much of its moisture on the mountains and dries as it heads towards the coast.
Dunedin was still sitting at 22degC about 5.30pm yesterday, the warmest temperature in New Zealand at the time.
Ms Blades said the expected high in Dunedin today was 18degC and then the temperature would taper off in the next few days as cloud cover came in.
