The weather on Midsummer's Eve will be largely fine and summery, the Finnish Meteorological Institute (FMI) says.
Temperatures are expected to rise above 20 degrees Celsius today, closer to 25 degrees in the south and west.
"The weather is quite warm, though rain showers will colour this Midsummer especially in the north and eastern areas," FMI meteorologist Eerik Saarikalle says.
Rain may also make appearances on southern coastal sea areas, brought in by a scattered cloud front. Thunder may also rumble in the south and north. Central Finland is likely to be the driest.
"But it won't rain all day anywhere in the country," Saarikalle says.
Real warmth over weekend
Midsummer's Eve may be on the fickle side, but the weekend proper promises to be exceptionally warm.
"We'll be breaking 25 degrees in the south and possibly central areas, too. The highest figures look to be at around 28 degrees Celsius," Saarikalle says.
Even still, bouts of rain and thunder will come and go.
A mass of warm air will be moving through Finland overnight on Saturday. That mass will not directly cause high temperatures, but daytime sunshine will push new summertime highs for the season.
"The air entering the country from the south will be very humid, real heat wave material. It may bring high-temperature thunder with it, but predicting them is difficult."
Thunder may strike at any time and their progress has to be followed with weather radar equipment. Local rainfall numbers may be high due to the strong showers.