How often does the temperature drop below -5 C
Spring and autumn have, on average, mild days and fresh nights but are changing and unstable. Surprisingly warm or cool weather occurs frequently in both seasons. In winter, sunshine is scarce; days are cold but generally above freezing with temperatures around 7 °C (45 °F). Light night frosts are however quite common, but the temperature will dip below −5 °C (23 °F) for only a few days a year. Snow falls every year, but rarely stays on the ground. The city sometimes sees light snow or flurries with or without accumulation.
Agassiz studied glacier movement in the 1840s at the Unteraar Glacier where he found the glacier moved 100 m (328 ft) per year, more rapidly in the middle than at the edges. His work was continued by other scientists and now a permanent laboratory exists inside a glacier under the Jungfraujoch, devoted exclusively to the study of Alpine glaciers.