The Marine Institute’s Malin Head Climate Station (55.371308°, -7.334328°) is the location of the longest running Sea Surface Temperature (SST) time series in Ireland and has been ongoing since 1958. This daily averaged temperature data product has been derived from a collection of measurements initiated by Met Eireann and continued by the Marine Institute, taken in and around Portmore Pier, using various techniques (well, bucket and modern sensor) and at various sampling intervals (daily to half-hourly). The aim of this time series data product is to standardise the temperature data across the different sampling methods, by removing diurnal signals and applying offsets to older measurements, through a robust and thorough methodology described in Daves et al., 2025 (under peer review). For further background see Cannaby and Hüsrevoglu, 2009. For the full-resolution data collection of measurement values see the ‘Malin Head Sea Surface Temperature data collection’ at this link: https://data.marine.ie/geonetwork/srv/eng/catalog.search#/metadata/ie.marine.data:dataset.4454. This standardised dataset provides a valuable long-term record of coastal ocean surface temperatures, which can inform on seasonal and interannual variation, along with regional ocean climate change.

The time series is split into three segments based on each SST collection technique at that time:

Segment 1 (28 April 1958 – 31 March 1991): two records per day, measured 2 m below the surface in a well on Portmore Pier in Malin Head connected to open water 30 m offshore.

Segment 2 (1 April 1991 – 30 June 2007): one record per day, measured in seawater extracted by bucket or by lowering a sensor directly into the water beside Portmore Pier

Segment 3 (16 November 2008 – Present): 30-minute frequency measurements from high quality sensors (Seabird SBE39 & 39plus) placed 3 to 4 m below OD Malin on Portmore Pier in a wave/weather-proof tube container. A mix of mid- and end-pier locations until 2012; end-pier locations have been used since then.

This dataset compiles these segments into a standardised, noon-centred, daily averaged time series. To make the time series as continuous as possible, diurnal signals have been removed from all segments of data and there have been correction factors applied to the data from Segment 2 to match it to the sensor data in Segment 3. Due to the differences in the pier and open-water water sources for Segments 1 and 3, there is no scientific basis for attempting to match the data for those segments, so there have been no offset corrections made to Segment 1 data in this dataset. This standardised temperature data product can be accessed by clicking on the Download link below. Associated data, including secondary sensors and data from shorter-term experiments (ran to improve the data collection) are made available through data request to the Marine Institute. These data have been collected for the purpose of long term monitoring for climate analyses.

Suggested Citation: Marine Institute. (2025) Malin Head Sea Surface Temperature daily averaged product, from 1958 to near-present [Data set]. Marine Institute, Ireland. doi: https://doi.org/10.20393/314DE8E2-79F0-4D36-B2BE-EE2A7E5590E2