Ukko, is a thunder and weather god in Finnish mythology, whose vital role is fertilizing fields with his thunder and rain.
Painting by Robert Ekman in 1867 called Lemminkäinen tulisella järvellä where Lemminkäinen asks help from Ukko ylijumala with crossing the lake in fire on his route to the wedding at Pohjola.
The fire spewing eagle kokko was thought to be the thunderbird, the cause of thunder, prior to the development of the idea of a human-form thunder deity. Lemminkäinen and the Fiery Eagle, Robert Wilhelm Ekman (1867).
Corded Ware culture boat-shaped battle axe from Närke, Sweden.
Ukonkivi (Ukko's rock, Inari Sami: Äijih) in Lake Inari in Lapland. Ukonkivi was a holy site to the local Sámi and archeological finds, apparently offerings, have been found there.
In Sámi shamanism, Western Sámi Horagalles, often equated with Eastern Sámi Tiermes, Baján, and Aijeke or Äijih, is the thunder god. He is depicted as a wooden figure with a nail in the head and with
Ukko
…Nom (lit. 'god, sky'): numi̬t č́ari̬ (lit. 'voice of Num/sound of the sky'). Similar meaning is found from some of the names of the Sámi thunder god: Aija, Aije, or Aijeke. In runic songs, Ukko is also given the epithet ylijumala (lit. 'High God'), which earlier writers have understood meaning Ukko's role as the supreme…
Depiction of Horagalles from a Sámi shaman drum found in Norway. The drum symbols were copied by the Christian priest Thomas von Westen in the 18th century.
Sámi people worshipping Horagalles or Tiermes. Copper engraving by Bernard Picart from Cérémonies et coutumes religieuses de tous les peuples du monde (1723–43)
The two hammers of the thunder god depicted as a blue cross on a late 18th-century shaman drum from Porsanger Municipality, Western Finnmark, Norway, described by the Christian missionary Knud Leem.