The land of Skyrim is the most rugged on the continent, containing four of the five highest peaks in Tamriel (see Places of Note: Throat of the World). Only in the west do the mountains abate to the canyons and mesas of the Reach, by far the most cosmopolitan of the Holds of Skyrim, Nords of the pure blood holding only the barest majority according to the recent Imperial Census. The rest of Skyrim is a vertical world: the high ridges of the northwest-to-southeast slanting mountain ranges, cleft by deep, narrow valleys where most of the population resides. Along the sides of the river valleys, sturdy Nord farmers raise a wide variety of crops; wheat flourishes in the relatively temperate river bottoms, while only the snowberry bushes can survive in the high orchards near the treeline. The original Nord settlements were generally established on rocky crags overlooking a river valley; many of these villages still survive in the more isolated Holds, especially along the Morrowind frontier. In most of Skyrim, however, this defensive posture was deemed unnecessary by the mid-first era, and most cities and towns today lie on the valley floors, in some cases still overlooked by the picturesque ruins of the earlier settlement.


http://www.imperial-library.info/pge/skyrim.shtml

Yes, I know that page...but there are no special informations about the different holds.

is anything known about the nature and environment in Whitehold/Skyrim?

About nature, Skyrim have werebears and werewolves.

Solitude, always one of the richest and most influential counties in Skyrim, has grown ever more powerful, controlling much of the northern coastline following King Thian's alliance by marriage with Macalla, the Queen of Dawnstar. It has sought to expand its influence further by annexing several former Imperial fiefs, such as the island of Roscrea, ruled directly by the Emperor since Uriel V conquered it in the 271st year. It has begun sponsoring exploratory missions even farther from the mainland into the misty waters of the Sea of Ghosts.

Winterhold, Solitude's ancient rival, has also experienced a renaissance of power and influence. Refugees from Morrowind, far from burdening the eastern city, have brought with them new ideas, enriching her culture and stimulating its old mercantile spirit. Scholars from all over Tamriel have descended on the county since it became home to the Ysmir Collective, a library rescued from destruction in the east, and the cornerstone of academic life at the College of Winterhold.

Hrothgar and Whiterun have not been as fortunate as their coastal northern cousins. A dynastic feud, attacks by H?rme bandits and frost trolls, and a series of annihilating winters of alternating floods, droughts, and fires has crippled the area that was once considered the Imperial City of Skyrim. The population blamed and then curiously exalted the leader of the local witches' coven, Jsashe, a self-proclaimed priestess of Lorkhan. The Witch-Queen of Whiterun, as she is called, now wields effective control of the county, though her magic has not brought it prosperity as of yet.