Recent forecast model runs from major centers like the European Centre for Medium-Range Weather Forecasts show Helsinki under a mild southwesterly flow with limited cloud cover on May 18, supporting surface highs near 19–20 °C. This places the market-implied consensus slightly above the long-term May average of 15–16 °C for the Finnish capital. Key differentiating factors include uncertainty in boundary-layer mixing and any late-day sea-breeze cooling from the Gulf of Finland, which could cap the peak at 19 °C or allow brief warming to 21 °C depending on exact timing of ridge passage. Updated model guidance issued in the last 24 hours has narrowed the spread, with most ensembles clustering in the 18–21 °C range and only small tails below 17 °C or above 22 °C.