*3.1. Duration and Amount Variation With Rain Type and Wind Direction*

During the 1096 days included in the study period, rain was recorded at least at one station on 515 days. The five wind directions had different frequencies and the most frequent wind directions were the westerly circulations SW and NW with a total of 739 days or two thirds of the time (Figure 3). More than half of these days included rain in at least one station. The easterly circulations accounted for less than 12% of the total number of days. SE had the lowest occurrence and the lowest percentage of rainy days. Both XX and NE had more than 40% rainy days.

**Figure 3.** Frequency of rainy days per year and per wind direction classes that represent large-scale weather types. Rainy days are days on which at least one station recorded five minutes of rain with an intensity of more than 0.2 mm/h. Error bars represent the 95% confidence intervals. Percentages above the white columns represent the overall occurrence of each wind direction and percentages below the columns represent the portion of rainy days in the total number of days within a specific wind direction. The dashed line represents the mean number of rainy days per year.

When examining the accumulated rain amount and duration, westerly circulations were the dominant wind directions with a contribution reaching 69% of the total rain duration (18,633 h) and total rain amount (21,705 mm) accumulated over all stations (Figure 4). Easterly circulations contributed less than 10% of both rain duration and amount. Convection contributed 36% of the total rain amount and occupied only 8.5% of rain duration. Southerly circulations had the highest proportion of convective rain with around 10% of the total rain duration and more than 40% of the total rain amount, while northerly, and especially northeasterly circulations had a low proportion of convective rain.

**Figure 4.** Prevalence of convective and stratiform rain types. Accumulated rain duration (**a**), and rain amount (**b**) per wind direction averaged over the stations and years. Error bars represent the 95% confidence intervals. The percentages on top of each column represent the proportion of accumulated rain within the respective wind direction to the accumulated rain in the whole year. The percentages below the columns represent the proportion of convective rain to total rain within the respective wind direction.

The mean stratiform rain intensity was 0.8 mm/h which only marginally varied with wind direction. On the other hand, the mean convective rain intensity of ~5 mm/h considerably varied across wind directions. The highest intensity was associated with SE circulations and the lowest with the NW circulations. Statistical data for each wind direction and rain type including standard deviation (SD) and standard error (SE) are summarized in Table 1.


**Table 1.** Summary of rain intensities (R) for wind directions in convective and stratiform rain.
