Ground-based atmospheric measurements at the Onsala Space Observatory (Sweden): data & trends (2009–2025)

This study presents a comprehensive long-term dataset of ground-based atmospheric observations collected at the Onsala Space Observatory (OSO), Sweden, between August 2009 and April 2025 (https://doi.org/10.1594/PANGAEA.984087, Mascaut et al., 2026a; https://doi.org/10.1594/PANGAEA.984085, Mascaut et al., 2026b). The dataset includes measurements of temperature, relative humidity, atmospheric pressure, precipitation, wind speed, gust and direction, and solar irradiance. It offers high-resolution insight into local weather patterns and seasonal variations, making it a valuable resource for climate monitoring and regional environmental studies. Preliminary analysis reveals a warming trend of ∼ 0.15 °C yr −1 , with significant seasonal contrasts: the most pronounced increase occurs in winter (203.3 % above the annual trend, so winters are becoming milder), followed by autumn (80.1 %), spring (62.3 %), and summer (32.9 %). Rain rate trends show a significant decrease over the study period. Anomalies such as the particularly cold winters in 2009–2010 and 2010–2011 or the particularly warm winter in 2019–2020 are highlighted an