Precipitation will increase and heavy rain events will intensify
Precipitation is projected to increase and heavy rain events to intensify with warming climate in Finland. In relative terms, the changes in winter will exceed those in summer and be somewhat stronger in the north than in the south. In winter, precipitation will increase from current levels approximately 10–40%, while in summer the change will most likely be quite small. However, precipitation in summer will remain more abundant than in winter also in the future.
Table of Contents
- There will be more precipitation in Finland in the future
- Precipitation will increase and intensify, particularly in winter
- In summer, heavy rain events will intensify but not increase in number
- There will be more and heavier precipitation also in spring and autumn
- Precipitation will increase more in the north than in the south
There will be more precipitation in Finland in the future
As the climate becomes warmer, precipitation will somewhat increase in Finland during this century , . However, the change takes place slowly, and during the next few decades, the impact of climate change may not necessarily be clearly detectable because precipitation has naturally great interannual variability , . Future precipitation is mainly estimated by using global climate models.
Until approximately the year 2040, precipitation will increase at roughly the same rate according to all the scenarios. (Scenarios describe possible future pathways for greenhouse gas emissions.) Annual precipitation at that time would be 7-8% higher than in the late 1900s. , .
In the latter half of the present century, projected precipitation depends considerably on the amount of greenhouse gas emissions. Even according to the low emissions scenario (B1), precipitation would, however, increase about 12% from the current level. Continuous increase in emissions (scenario A2) would increase precipitation by more than 20%.  Projected changes in annual precipitation are shown in Figure 1.
Figure 1. Projected change in annual precipitation in Finland in 2000-2100 compared to the mean of the period 1971–2000 (in per cent). The projections are mean values for the results of 19 climate models, shown separately for three greenhouse gas scenarios (A2: high emissions, A1B: moderate emissions and B1: low emissions). 
Precipitation will increase and intensify, particularly in winter
Precipitation is likely to increase and heavy precipitation events to intensify in the future throughout the year, but the inter-annual variability of precipitation might increase to some extent.  The projected changes in precipitation in different months are shown in Figure 2.
In relative terms, precipitation will increase the most in winter. During that season, an increase of 10-40% for precipitation is projected by the end of this century compared to the period of 1971-2000 . In addition, the number of days with precipitation is projected to increase in winter , . Simultaneously, the longest dry periods without any precipitation will shorten by about 10% . Total precipitation will still remain smaller in winter than in summer also in the future.
Also precipitation events will intensify the most in winter, but most of heavy precipitation events will occur in summer also in the future , . Owing to rising temperatures, an increasing proportion of winter precipitation will pour down as rain. 
Figure 2. Projected change in precipitation in per cent for 2070–2099 compared to 1971–2000 in Finland for each month. The curve indicates the mean for the results of 19 climate models, the vertical beams display the 90% probability interval calculated for the change. The figure to the left shows A2-scenario (high emissions), the one to the right B1-scenario (low emissions). All results are mean values for the whole of Finland.  More recent projections also exist about changes in precipitation but they hardly differ from the ones presented here 
In summer, heavy rain events will intensify but not increase in number
The summer will continue to be the season with most abundant precipitation also in the future. As a result of climate change, summer precipitation will more likely increase than decrease: according to climate projections, an increase of 0-20% will be realized by the end of the present century compared to the years 1971-2000 , . The reason for this is that precipitation events will intensify . Although heavy precipitation events will intensify relatively less in summer than in winter, the heaviest events will probably still occur in summer and early autumn.  In summer the heaviest precipitation events may increase by 10–25% .
There will be more and heavier precipitation also in spring and autumn
Climate change is likely to increase precipitation also in spring and autumn, although to a lesser extent than in winter. However, climate models provide different projections for the number of days with precipitation , . According to the model projections, there is still some uncertainty whether dry periods will become prolonged or shortened in spring and autumn , . Heavy rain events will, however, intensify in the future .
Precipitation will increase more in the north than in the south
According to the climate model results, precipitation will increase slightly more in northern than in southern Finland. In the north, precipitation will increase in all seasons, but the change is most pronounced in winter. Correspondingly, the number of rainy days will increase except in summer. In contrast, dry periods without any precipitation will mainly become shorter in northern Finland. 
In southern Finland, precipitation will increase in all seasons except in summer when it will remain almost unchanged . Number of days with precipitation will increase in the south in winter, but in summer it may even slightly decrease . Similarly, dry periods without any precipitation will become shorter in winter, whereas in other seasons only small changes are projected for the length of the dry periods. In summer, the dry periods may even become slightly prolonged. , .
Table 1. An indicative description about seasonal changes in precipitation in southern and northern Finland by the end of the present century (winter: December-February, spring: March-May, summer: June-August, autumn: September-November). “Unchanged” means that no significant change is expected.  and  updated.
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