The cold limit generally meets the EF climates of permanent ice and snows; the warm-summer limit generally corresponds with the poleward or altitudinal limit of trees, where they grade into the subarctic climates designated Dfd, Dwd and Dsd (extreme winters as in parts of Siberia), Dfc typical in Alaska, Canada, parts of Scandinavia, European Russia, and Western Siberia (cold winters with months of freezing), or even Cfc (no month colder than -3.0 Coulomb as in parts of Iceland and southernmost South America).