The paper analyses the position of the oceanic temperature frontal zones in comparison with the spatial distribution of the amplitude of the seasonal variability of water temperature and gradients of amplitude in the North Atlantic. The paper also considers the change in the amplitude of the water temperature seasonal variability along meridional surface transects through the Gulf Stream front, Subtropical and Arctic Fronts. The authors use data on the potential water temperature at 0.5 m depth of the ORAS5 ocean reanalysis (1958–2021). The position of frontal zones is determined based on the calculation of horizontal water temperature gradients. The amplitude of the water temperature seasonal variability is calculated as half of the difference between the maximum and minimum temperature in the mean annual cycle. It is noted that high values of the amplitude of water temperature seasonal variations are observed in the mid-latitudes, decreasing in the northern and southern directions. In the equatorial zone, Tropical Atlantic and Arctic, the range of water temperature seasonal variability is minimal. The extended areas with a sharp change in the amplitude of the water temperature seasonal variations were found to coincide with the position of temperature frontal zones. The correlation coefficient between the spatial distribution of temperature gradients and gradients of its seasonal variation amplitude was 0.93. The Gulf Stream front bordering the waters of the Labrador Current separates the regions with the largest difference in the water temperature seasonal variability. The difference in the amplitude of the water temperature seasonal variations in the areas located on both sides of the Gulf Stream, Subtropical and Arctic fronts was mainly due to the winter temperature difference. The obtained results show that the frontal zones in the ocean separate regions not only with different thermohaline characteristics, but also with different amplitudes of the seasonal variability of surface water temperature.