A longer summer season attracts people to spend their holiday in Finland
While summers become warmer and longer, extreme weather events may also become more common. Recreational use of water bodies is expected to become more popular, although blue-green algae blooms – particularly in the Baltic Sea – will restrict this. Tourism will benefit from the climate change and the Finnish summer should be marketed to foreign travellers more strongly than now.
Extreme weather events increase
In the northern latitudes, the climate is projected to warm more strongly than in the rest of the globe.  However, the temperature change is smaller in the summer than in the winter. According to the average of the projections performed with climate models, by the end of the century, the summer temperatures should rise by 2–4 degrees in Finland. The highest temperatures are estimated to rise and the hot weather periods become more common.  Before the end of the century, the number of hot days is projected to increase to 3–4-fold. In addition, as the climate warms, the summer season becomes longer. 
Depending on the greenhouse gas scenario used, the annual rainfall is estimated to increase by 12–22 per cent. Increase of rainfall is expected to be less severe in the summer than in the winter and, in some simulations, rainfall in the summer might even be reduced to some extent.  Since the warm atmosphere of the future can include a higher concentration of humidity than now, heavy rain may become more common.  In addition, climate change is expected to intensify storms and floods. 
Global warming will also warm the temperatures of water bodies; the surface temperature of inland waters and sea water will rise approximately as much as the air temperature. With respect to inland waters, particularly the highest surface temperatures are expected to rise from the current values: in some lakes the change may be as much as five degrees.  
Warm summers attract swimmers
In the main, climate change has more positive than negative effects on summer activities. Although a threat exists that extreme weather events become more common, a warming climate and longer summer period improve the possibility to engage in many hobbies. Climate change is estimated to have the biggest effect on activities that require high temperatures and sunshine, such as swimming. 
As the air and water temperatures become warmer, swimming in natural waters is expected to increase. In addition to causing overcrowding at beaches, increased popularity of swimming may increase the maintenance costs of beaches. On the other hand, in the future, swimming will be impeded by increased frequency of algal blooms and poorer water quality – particularly on the coast of the Gulf of Finland. If the quality of sea water deteriorates, demand for outdoor swimming pools and travelling near inland waters may increase. 
Longer tourist season
With respect to summer travelling, effects of climate change are mainly positive. Warmer summers are likely to increase domestic travelling. In addition, for tourist entrepreneurs, a longer summer season is a positive issue as it prolongs the travelling season and may help to even out the rush seasons in tourist destinations. On the other hand, timing of the school summer holiday is usually the most important factor influencing the timing of the holiday season. So, also in the future, travellers are unlikely to time their holidays in the early or late summer. Tourist businesses should utilise the prolonged summer season by marketing Finland to foreign tourists who have their holiday season later than in Finland, particularly, if the travel destinations in southern Europe become too hot. 
However, if rain increases during the summer, actual benefits of the longer summer season are still somewhat uncertain. According to tourist businesses operating in the Finnish lake district, tourists are unwilling to canoe, take boat rides or hike if the weather is too rainy or stormy. In addition, entrepreneurs might not be willing to take the risk of arranging programme in unpleasant or dangerous circumstances. 
Blue-green algae – challenge of the Baltic Sea
As the summers become warmer and longer this will also have an effect on the recreational use of the Baltic Sea. Warm weather attracts people to the water to seek refreshment. Thus, spending time at the summer cottage, boating and recreational fishing are likely to increase their popularity. 
However, the recreational use of the Baltic Sea may be hindered by an accelerated growth of blue-green algae and extensive blooms becoming more common during mid-summer or the most popular holiday season.   Buyers of summer houses are already interested in the likelihood of algal blooms in the Gulf of Finland and the Finnish Archipelago, so in the most algae-infested sea areas, popularity of summer cottages may even decrease in the future.  With respect to the recreational use of the Baltic Sea, eutrophication should be controlled or the blue-green algae blooms may decrease the positive effects of the warming climate.