Weather patterns in Sweden
April: – Still extremely cold, and snowstorms are possible. Swedes who sail at this time have central heating in their boats
May: – Spring arrives. The season is very short, often only two weeks long, accompanied often by sunshine. It can get very cold on clear nights. It is still dangerously cold in the water.
June: – Summer begins, and rapidly becomes hot and dry. Periods of week after week of cloudless blue sky are not unusual. If this occurs, the sea will warm up quite quickly, and in the Stockholm Archipelago will often be suitable for bathing by the end of June. A reliable afternoon sea breeze gives easy passage making. There is daylight from about 0400 to 2200.
July: – Paradise month – usually sunny, warm and dry, though localised thunderstorms are not infrequent. The sea breeze l0 miles out can reach F 4-5 every day. This is the time when most of Sweden, Denmark and Germany take their holidays, so guest harbours and the prettiest natural anchorages fill up by late afternoon. There will probably be somewhere, but maybe not your first choice. A solution is to leave early and get in early, just after lunch, or go into a harbour at midday, get supplies, leave and anchor for the night.
August: – Will still be sunny, but chilly when the sun disappears. Water is getting colder every day unless the sunshine persists. Clear nights may be very cold.
September: – Late for cruising. The light is going and cold weather is approaching.
Of course, nothing is guaranteed; cold wet summers do occur and sometimes severe storms
Weather patterns in Denmark
Most of Denmark lies on similar latitudes to northern Britain and weather patterns are not so dissimilar. British weather tends to arrive in the Western Baltic one to two days later.
April is dry but can be cold and frosty with temperatures near or at zero overnight even in late April.
May is warmer. Fog is rare and visibility is usually good. In May there can be long periods of easterly winds; later the prevailing winds are westerly.
June, in particular, is a lovely month with long daylight hours. There is a prolonged twilight and only about 5 hours of darkness.
July tends to be warmer, but high pressure may bring cooler winds from the north.
Wind strengths in Summer seldom reach F7 but if the UK suffers a summer of gales, expect these to reach western parts of Denmark a day or two later. July and August may bring a persistent high with Mediterranean conditions, but this only happens every few years and the more common pattern is for changeable weather.
August, particularly, as elsewhere, winds can be variable with squalls under the clouds and violent thunderstorms.
September can bring gales and shorter days. This marks the end of the sailing season for most, but some “locals” in the south do not haul-out before mid-October.
The peak of the sailing season is late June to early August when schools are on holiday and there are many visiting yachts from Sweden and Germany. It may then be difficult to find a berth even in the larger harbours and marinas. There are however numerous anchorages in the many sheltered fjords. From Mid-August, schools re-start and holiday activities start to close.