Kashubian Lake District
Kashubian Lake District is a mesoregion part of the Eastern Lake District macroregion, the northernmost of all Pomeranian lake districts. Nearly of the lakes lie at a height from 149 to 216 metres above sea level. The mesoregion is largely populated by Kashubians, from which the name of the region originates. However, because Kashubians also live in the nearby mesoregions, the alternative name for the lake district is the Kartuskie Lake District.
Borders
The Kashubian Lake District, according to the division made by Konradzki has an area of about 3000 km km2. To the north, the mesoregion borders with the ice-marginal valley of the river Reda and the river Łeba; which separates the lake district away from the Żarnowiecka Upland, and the Damniacka Upland. From the east, the lake district is bordered by the Kashubian Coast. Beyond, the region borders with the Starogradzkie Lake District, from the south-east, the region is bordered by the Tucholski Forest. The western border is closed in by the Polanowska Upland.The Kashubian Lake District is located in the following powiats: Gdańsk, Gdynia, Bytów, Gdańsk, Kartuzy, Kościerzyna, Lębork, Słupsk, Starogard, Tczew, and Wejherowo.
The northern and eastern borders are very clear, and in physiographical terms in this part of Poland are identical. The rest, meaning the western and southern borders, and the new border of south-east, according to J. Konradzki, have the border less geographically separated due to the lack of geographical features.
Terrain relief
The terrain relief of the Kashubian Lake district is undulated, especially in the surrounding of the Kartuzy. The relief is much more stronger in the other mesoregions of the voivodeship, sometimes closely resembling an upland relief, where there are deequalisations of the terrain. In some places, some of the undulations have heights up to 80 metres. The differences between the lowest and highest peak is 160 metres.The relief of the Kashubian Lake District was caused by several factors: the Scandinavian ice sheet, and river-glacial forms, causing U-shaped valleys. This has caused the region to be labelled a glacial region. Another factor contributing to the relief of the land is the accumulated erosion caused by the rivers.
The moraine uplands dominate the landscape of the mesoregion. The layout of moraines forms homocentric ellipses in the land. The longer pivot of these ellipses agrees more or less with the axis NEE-SWW. However, this isn't an absolute rule for the region, as for example, the ellipses lying in the centre of the Szymbarskie Upland are oriented on the axis E-W.
Both the arrangements of postglacial channel-type lakes and the waterway network have a similar arrangement to radial, reflecting arrangement of gashes of a domed structure area, with the direction however dominating the axis NNE-SWW. The depths of postglacial channel lakes in the Kashubian Lake District are achieving a depth between 20–40 metres and the width with an average from 200 up to 1500 metres. The length of single funnel-like lakes fluctuates from 1 km up to 24 km. The inclinations of the slopes reach in places up to 40 °. Single funnel-like lakes often link with river systems e.g. Raduńskie Lakes. A similar formation, found in the Tuchola Forest according to the division of Kondracki, is that of the Wdzydze Lake; on that account included by some researchers, like that of Augustowski to the Kashubian Lake District.
Waterways
According to the regionalisation drawn up by the Ministry of the Environment, the Kashubian Lake District lies, as a whole, in the region of the Lower Vistula, and so its waters are subject to RZGW in Gdańsk. In the Kashubian Lake District, there are over 500 lakes, the relation of the surface area of natural bodies of water, to the surface area of their drainage basin, is 3.5% of the mesoregion. The majority of lakes are of postglacial origin. Most of the lakes are postglacial channel lakes. The flowing rivers through mesoregion, split up the region on all sides, they are all in the drainage basin of the Baltic Sea.The mesoregion is able to be split in the following river basins: Radunia Reda, Łeba, Motława, Wierzyca, Słupia, and Łupawa. In the division made by Augustowski, and by Kondracki, this region still includes the Wda and Brda river, which do not belong to mesoregion.
Climate
The Kashubian Lake District belongs to the Pomeranian Lake District. There are many meteorological stations found in the Kashubian Lake District. Unfortunately the costs limit the meteorological stations to local changes in temperature, pressure, the wind speed, and similar parameters. The whole of the knowledge about the climate in the Kashubian Lake District comes from field research and meteorological stations found in health resorts. Additionally, the Kashubian Lake District has a large variability in weather, which is quite characteristic feature to the region.Temperature
The temperature in January, in the centre of the mesoregion is lower than on its edges – particularly in the Tricity, where the amount in temperature change is about 2.5 °C; similarly in July, however the difference is smaller, scarcely differentiating about 1 °C. Additionally, the length of the vegetation period is about 5–10 days shorter than in neighbouring regions.| Month | January | February | March | April | May | June | July | August | September | October | November | December |
| Maximum temperature | 0,7 | 4,5 | 10,4 | 16,3 | 19,7 | 21,1 | 21,0 | 16,5 | 11,5 | 5,1 | 1,4 | |
| Average temperature | 0,4 | 5,5 | 11,1 | 14,8 | 16,5 | 16,1 | 12,3 | 7,9 | 2,9 | |||
| Minimal temperature | 1,8 | 6,6 | 10,4 | 12,4 | 12,4 | 9,3 | 5,4 | 1 |