Warm conditions will prevail in most of Finland through Thursday, according to the Finnish Meteorological Institute (FMI).
Highs in southern and central areas on Wednesday will reach 22-25 degrees Celsius.
Forecasters said the 25-degree 'heat threshold' may break in the regions of Satakunta and Ostrobothnia.
On Tuesday the mercury surpassed 25 degrees in Vantaa, Hyvinkää and Mäntsälä. The FMI said it expects similar temperatures in these areas on Wednesday.
Temperatures are cooler up north, where highs are expected to remain below 15 degrees as showers are in store on Wednesday afternoon. But as warm air continues to flow north, temperatures in southern Lapland could reach 20 degrees by Thursday.
On Thursday southern and central parts will continue to bask in summer-like weather, although punctuated by a few scattered showers, according to the FMI.