Climate in Lithuania is temperate continental. The population density is lower than in the Western Europe and large parts of Lithuania are covered by forests and agricultural pastures. While wild animals are not an everyday sight you may be lucky enough to see rabbits, deers, wild boars or other animals beside the roads.
In Vilnius the average highest daily teprature in July is 22,1 C, average lowest daily temperature in July is 12,3 C. Average highest daily temperature in January is -3,5 C whereas lowest average daily temperature in January is -8,7 C.
Typically there are several very hot weeks in summers (with daytime temperatures surpassing 30 C) and one or two very cold weeks in winter (with nighttime temperatures going under -20 C).
Close to the sea in Klaipėda the winters are milder and the summers are cooler, but the difference does not exceed a couple of degrees. Lithuanian terrain is extremely flat (all country under 300 m), meaning there are no altitude-induced climate differences.
The precipitation is never a major issue and varies little. July is the wettest month with 77 milimeters of rain. In winter it snows but the snow cover is rarely stays for more than a couple of days before melting (however, there are many such "snow periods" every winter).
If you come from outside Europe it may surprise you that Lithuania is quite far to the north: further north than any US, Canadian, Japanese or Chinese major city. While the warm Gulf Stream supports its temperate climate and never allows Klaipėda port to freeze, it could not change day/night cycle. High latitudes mean that in the deep winter the days are quite short (7 hours) whereas in mid-summer they are very long (17 hours), with nautical twilight lasting the whole night. Daylight savings time mean that winter sunset is even earlier, getting dark ~4PM.
That said every season in Lithuania has its own beauty as the nature paints itself in different colors. Contrary to popular belief winters are not perpetually white, but you have high chances of encountering heavy snow if you visit in January or February. The autumns are universally yellow as the leafs of every tree prepare to fall down. The springs and summers are green, although during the droughts everything may start gaining a yellow shade earlier.
There are no natural disasters like volcanoes, earthquakes or tornadoes. Forest fires do happen, but they are minor compared to the ones raging in Australia or Southern Europe. The cold in winter takes its toll sometimes but this is limited to the homeless. Heavy rains and strong winds do some damage, but usually only to the property and crops and this damage is minor compared to places like the United States.