The Metservice did not immediately have figures for Greymouth yesterday, but said in Hokitika the temperature had made it past 20C only once this month.
On January 2 it reached 21C but just four days later, struggled to just 14C.
Most days the temperature has sat stubbornly at between 16 and 18C.
Lake Brunner rose so high last week, with the Crooked River in flood, Iveagh Bay was temporarily cut off.
Beaches are also quiet - weather data from NOAA, which is used by officials, shows the current sea temperature off Hokitika is 16.1C.
The average maximum is a far warmer 20.8C with the average 17.7C.
Robbie Barrow from the Kahuna Boardriders said surfers would agree it was considerably cooler than normal for January.
"We put it down to the unremitting westerly south-westerly weather systems. We expect it to warm up however.
"March/April is when our inshore water is warmest."
Kotuku Surf Lifesavers chairman Mark Bolland said this time last year in Greymouth the sea temperature was about 18C, but currently it was 15C.
Neville Winter from the Lake Brunner Coastguard was stoic.
"The lake is probably up to 18 or 19C. It doesn't change a lot."
The beaches on the western shore were the warmest spots, he said.
"And it's one of the warmest lakes in the South Island."
Meanwhile, the Metservice says a potential weather bomb is brewing.
Communications meteorologist Lisa Murray said the approaching low would undergo a process called "explosive cyclogenesis" - deepen rapidly. It could become a weather bomb.
From 9pm today until 3am on Thursday, 300 to 400mm of rain is expected in the Westland ranges, with 90 to 140mm about the coast. In Buller there could be 60 to 100mm about the coast.
The website Accuweather, which accurately predicted the wet January, shows an improvement from the first week of February.
- Greymouth Star
