A large pool of unusually cold water in the Tasman Sea should give swimmers along the NSW coast a bit of a shock over this year’s Christmas and New Year holiday period.

The map below shows that sea surface temperatures across the western Tasman Sea were hovering around 1 to 3ºC below average in the lead-up to Christmas this year.

Image: Sea surface temperature anomalies on Wednesday, December 21, 2022. Source: Bureau of Meteorology.

The region between South West Rocks and Batemans Bay is particularly cold, which encompasses some of the state’s most popular holiday beaches.

Air temperatures are predicted to reach the mid-to-high twenties along most of the NSW coast between Christmas and New Year’s Eve. However, water temperatures will be near or below 20ºC for much of the coast.

Earlier this month, the Bold and Beautiful Swim Squad at Manly Beach were reporting water temperatures of 19.4ºC near the beach. At a similar time in December last year, the water temperature was sitting around 20.4ºC at the same location.

Data from the Australian Integrated Marine Observing System’s website revels that water temperatures in parts of the western Tasman Sea are currently in the lowest 10 percent of historical records, based on data between 1992 and 2016.

Image: Sea surface temperature precentiles on December 21, 2022. Source: IMOS

This unusually cold water to the east of NSW is a stark contrast to the start of 2022, when water in the same region was in the top 20 percent of records.

You can track the latest sea surface temperature anomalies in the Tasman Sea here.