The Grimsel Pass is a mountain pass in Switzerland, crossing the Bernese Alps at an elevation of 2,164 metres. The pass connects the Haslital, the upper valley of the river Aare, with the upper valley of the Rhône. In so doing, and as the Aare is a tributary of the Rhine, the pass crosses the continental divide between the North Sea and the Mediterranean Sea.
A paved road follows the pass, running 38 kilometres from Gletsch to Meiringen. The road is normally closed between October and May, due to the high snowfall on the pass. As it is the only direct road pass between the cantons of Bern and Valais across the Bernese Alps, attempts are made to keep the road open as long as possible with snow ploughs. A PostBus Switzerland service uses the pass several times a day, connecting Meiringen and Oberwald.
Due to the high altitude of the pass, and its continental location, the climate is cool or cold all year round, and receives a fair amount of precipitation year-round (the majority of which is snow). Snow usually falls from late September until late June, although during cool spells, it can snow at the height of summer. Most years, permanent snow fields remain at the pass, due to the temperature rarely rising above 15 °C. This area has a long winter season, with little precipitation mostly in the form of snow, and low humidity.