Synoptic atmospheric conditions drive microclimatic variability in a high-latitude landscapes

Microclimatic heterogeneity in high-latitude landscapes plays a key role in shaping ecosystem functioning, biodiversity and resilience to environmental change. Microclimates are shaped by topography, vegetation and synoptic atmospheric conditions. However, the translation of macroscale synoptic conditions into fine-scale temperature variability has rarely been investigated empirically.We examined summer near-surface temperatures in relation to synoptic conditions (classified from calm and clear to windy and cloudy) and analyzed changes in microclimatic drivers and spatial heterogeneity. The study was conducted in a high-latitude landscape, utilizing macroclimate data from weather stations and microclimate data from a dense network of 193 stations distributed across a heterogeneous landscape characterized by a strong environmental gradient.Our results revealed that fine-scale temperature heterogeneity is strongly connected to synoptic conditions. The temperature range across the landscape was highest (10°C T _min and 16°C T _max ) on calm, clear days, whereas on windy and cloudy days differences were significantly smaller (5°C T _min and 7°C T _max ). Macroscale variations influenced microscale temperature heterogeneity differently depending on landscape properties: topography primarily affected minimum temperatures, while both topography and vegetation properties contributed to variations in maximum temperatures.Our findings highlight the variation in microclimate temperature heterogeneity across a high-latitude landscape, largely driven by synoptic conditions that regulate air mixing and radiation fluxes. By demonstrating how large-scale atmospheric patterns influence fine-scale thermal variability, our results offer deeper insight into key microclimatic drivers under different weather conditions. This understanding is crucial for predicting how microclimates will respond to climate change in high-latitude ecosystems.