Shetland can be a very windy place. The average wind speed over the year is around Force 4 (15mph, or 24kph) and, in winter, speeds of hurricane force 12 are not unknown. Gales are much less common between April and September, though, and there can be flat calm days at any time of year. The islands are quite hilly, with many sheltered coastal coves (called geos in Shetland dialect), so it’s usually quite easy to find a sheltered spot for a picnic.
Fog occurs mainly in summer but is often confined to the east coast of the islands while the west side bathes in sunshine. Flights to and from Sumburgh, as well as internal flights, can be affected.
Although Shetland's as far north as Greenland's Cape Farewell, snow rarely lies long. Gales of rain, squalls of sleet and occasional 'days between weathers' characterise the long winter, but frosts are rarely severe or prolonged.