Climate. – Located in a transition zone where the influences of the sub-Atlantic climate of NE Russia intersect with those of the sub-continental climate of NW Germany, Latvia is characterized by a considerable variability that strongly decreases the value of the averages and makes the trend of crops is very uncertain. The climate of the coastal localities, especially those facing west, which have their ports always free from ice, is mitigated by the Baltic; the continental influences then grow gradually towards the interior, as evidenced among other things by the fact that the lines that mark some floristic limits have a regular course parallel to the coast; the annual excursion, which is 18 °, 5 in Liepāja, already rises to 21 °, 3 in Jelgava and is 23 °, 8 in Kārsava (near the Estonian border); the delay of winter in coastal locations must also be attributed to maritime influences. In January, Latvia is between the isotherms of – 3 °, 5 and – 7 °, 5; in July between 16 ° and 19 °, while the annual average oscillates between 5 ° and 6 °, 5. Riga, which in January averaged – 4, 3, had in the same month exceptionally a year up to 2, 3 and another – 17, 1; July, which is usually 17 °, 5 ° on average, saw exceptionally average temperatures of 22 °, 5 and 14 °, 8 °. Prevailing winds are those of SW.; in winter, those of S., continental ones, blow mainly; in summer those of O., marine. Precipitation, on average 550-700 mm., Is greater along the coast and in the hilly areas, with prevalence in the summer months and in November-December. In Riga there are on average 179.4 days with rainfall each year, of which 47.6 in autumn and 40, 8 of spring; days with snow average 51.3 with a maximum of 10.4 in January. The average winter fog is noteworthy. In Daugavpils the Daugava, as mentioned, is frozen for 107 days; the first ice appears around 18 November and the last ones disappear around 9 May; between 12 December and 29 March the river is completely frozen.
Flora. – Latvia is located in a transition region between West and East on the one hand and between North and South on the other, so as to constitute, together with Estonia, a second order phytogeographic unit. The climate, mild and humid near the coast, allows the life in some privileged places to plants of our countries, which have their northern limit here (Taxus baccata, Hedera hlix, Myrica gale, Erica tetralix, Trapa natans, especially along the coast of Courland, where an area was called by the Germans, thanks to its climate, Gottesländchen); they live in contact with Nordic and continental species (Digitalis ambigua, Agrimonia pilosa, Silene tartaric and viscous). The current floristic mantle is, moreover, the result of the climatic conditions of the last millennia, as appears from the fact that many plants, which have spread over more lukewarm interglacial periods, are now unable to complete their entire vegetative cycle. The beech is excluded from the area as its northern limit is already outside it. On the other hand, fir and pine find good development conditions, as do the less demanding broad-leaved trees, oak, alder, birch. Even the associations of plants show the same characteristics of the single essences and while in some places there are forms similar to the tundra, elsewhere the central European forest stands out in all its majestic beauty. Intermediate characters, with infinite transitional forms, present many associations of meadow (or moorland) with the wood, which derive from a primitive agricultural exploitation, which allows to obtain hay from the places where some trees have been felled. In the humid lowlands there is a vegetation of Sphagnum, in those steppes of Calluna.
Fauna – The fauna of Latvia does not include characteristic elements but, given the geographical position of the region, it falls within the limits of the Northern European and more precisely Baltic fauna.
Various species of mammals populate the region and among these various Bats, Insectivores, Carnivores, among them, the lynx, the wild cat, the wolf, various species of mustelids, the otter, etc. Various are the Rosicants and among the Ungulates the elk. Quite rich is the avifauna with many species of nests. The reptiles, amphibians and freshwater fish are less richly represented. Among the invertebrates numerous insects, especially beetles; the Myriapods and the Arachnids are fairly represented together with the terrestrial and freshwater malacological fauna.
