Lake Morphometry Influences the Accuracy of SWOT Estimates of Water Level

Lake water surface elevation (WSE) data in Sweden are needed to understand water supply and ecosystem services provision. SWOT can complement WSE in situ measurements, but the influence of lake shape on its accuracy remains unclear. We explore the performance of the SWOT pixel‐cloud and this influence across 62 lakes from August 2023 to November 2025. We found that SWOT estimated WSE with a mean error of about 5 cm in lakes larger than 1 km 2 . Winter ice reduced the number of usable observations in northern lakes, but SWOT still captured major WSE changes when data were available. The influence of lake morphology on SWOT accuracy occurred mainly through shoreline effects reflected through the compactness of the lakes. These results show that SWOT provides useful WSE information in Sweden, but that lake morphology cannot be ignored.