This study aims at providing robust temperature reconstructions for a key oceanographic setting in the North Atlantic and at understanding the nature of the temperature signal recorded by the two biomarkers U k′ 37 and TEX 86 , considering season and depth of production. To do so, high-resolution signals of U k′ 37 and TEX 86 are determined for the last 70 kyr for core MD95-2042, located off Portugal. Signals of U k′ 37 and TEX 86 present a tight correlation, demonstrating a dominant temperature effect. U k′ 37 signals correspond well to the annual mean sea surface temperature (SST), whereas TEX H 86 -derived temperatures are 5.6°C higher, which is unrealistically warm for this area. Unsuitable TEX 86 global linear calibrations on the Iberian Margin may suggest a possible occurrence of archaeal communities with specific temperature response. To assess the impact of different season or depth of production of the biomarkers on the recorded temperature in the sediment, modeled temperature proxies (Tproxies) are introduced in a Regional Oceanic Modeling System and tested for different seasons (annual/summer/winter) and depths (surface and 0-200