Impact of Teleconnection Patterns on the Thermal Growing Season in Central and Northern Europe

This study aimed to assess spatiotemporal changes in the thermal growing season (TGS) and its correlation with teleconnection patterns in Central and Northern Europe from 1950 to 2022. Gridded temperature data (0.25° × 0.25°) from the European Climate Assessment and Dataset [ECA&D] reanalysis and atmospheric circulation indices (East Atlantic [EA], North Atlantic Oscillation [NAO], Scandinavia [SCAND], East Atlantic/Western Russia [EA/WR]) from the Climate Prediction Center (CPC) were used. TGS was defined as the period from the first 6-day sequence with mean daily temperature (T_mean) >5°C after the last spring frost (T_mean <0°C) to the last 6-day sequence with Tm_ean <5°C after the first autumn frost. The analysis revealed significant spatial and temporal variation in TGS start and end dates. On average, the growing season began on 24 April and ended on 30 October. The earliest onset (February) and latest end (December) were observed in the southwest, while northern Scandinavia experienced the shortest season (June–September). Teleconnection patterns influenced TGS timing as follows: positive phases of EA and NAO led to earlier starts and later ends, especially in Western Europe, whereas SCAND+ accelerated the onset in the north. SCAND and EA/WR had more variable effects on the end date. Extreme values of the circulation indices caused significant shifts in TGS timing. The results highlight the key role of atmospheric circulation in shaping the variability of TGS in Europe and its temporal shifts, which have important implications for agriculture in the context of climate change.