As the Vikings relied upon the sea for their travels it is important to realize that they also relied upon the weather which could make sailing an impossible feat due to strong winds and high seas. It was crucial that the Vikings understand basic weather characterists that each season brought as they could then plan their voyages whether long or short.
Climatology: The science that deals with climates and their phenomena.
Climate: The average course or condition of the weather at a place over a period of years as exhibited by temperature, wind velocity, and precipitation.Essentially, climatology is the study of the climate in a scientific manner. The Vikings did indeed take heed of the weather and planned their journeys according to the season. A voyage during the late fall or winter was one of a fool as phenomenal seas and ferocious winds would sink a Viking ship in a rapid manner.
The following paragraphs will break down the climate for the Danish Straits, the Southern and Central Baltic Sea:
A climatological “Icelandic Low” dominates the Baltic region north of 40 degrees north during the winter. This feature influences the numerous Atlantic storms which move through the Baltic region bring rain or snow, and gales, while long periods of bleak, drizzly weather accompany the weaker storms that form along slow-moving fronts. Complex storms are usually slow and intense. In advance of these systems, the flow over the area region is generally southwesterly, sometimes reaching gale force and often accompanied by widespread light rains. As the fronts move through the region they can produce shifting gusty winds, precipitation and sharp temperature drops.
Autumn through early winter are the worst seasons along the Baltic shores. Rainy, foggy days, cool temperatures and mostly overcast skies dominate the area. Cloudy days which numbered less than a dozen in September become more frequent, growing to an average of 18 to 22 days in December. Clear days occur on an average of 1 or 2 days in December. During this season, rain and snow frequently occur with average precipitation amounts are f1 to 3 inches per month. Snowfall occurs 8 to 14 days per month.
The real snow season is from December through March. Below freezing temperatures are common by October. In November average nighttime lows are around freezing with average daily maximums in the 40’s (F). When humidities are high and nighttime skies are clear, and conditions are calm, there is an excellent chance for “radiation fog“.