STUDIES ON THE VEGETATION OF ICELAND 5 
tember, and we find also, that only on the south and west coasts 
is the temperature of the air, on the average, always lower than 
that of the sea water, whereas on both north and east the tempe- 
rature of the air may remain for months higher than that of the 
sea water, this being especially the case on the east coast. 
The Polar Current carries with it great masses of ice. This 
current of ice can either strike Langanes or the east coast of Vest- 
firdir, south of Cape Horn. If it strikes Vestfirdir, then it is borne 
by the eastward going current along the north coast, rounding 
Langanes and drifting on along the east, sometimes even also along 
the south coast, until all the ice has melted or disappeared out into 
the Atlantic. When the current of ice strikes Langanes or Melrakka- 
sljetta, it is carried out into the Atlantic by the same current. The 
quantity of drift ice varies to an extraordinary degree; in some years 
there may be none at all, while in others, “ice years”, it may lie 
about until far on in summer. The result is seen in great climatic 
fluctuations. 
The winds in Iceland are determined by two centres of low 
barometric pressure, one lying south-west of Iceland, and another, 
minor one, situated towards the north-east. The former constitutes 
the principal factor in determining the state of the wind, and in 
consequence, easterly winds are most prevalent, especially on the 
west. In East Iceland, the eastern minimum is of no slight im- 
portance, westerly winds being here of more frequent occurrence 
than in other parts of the country. 
The highest frequency percentage for calm occurs in summer, 
and this applies to all parts of the country; the highest percentage 
is recorded from the Vestmannaeyjar, with an average value of 22, 
a percentage of calm in winter of 10—20 and in summer of 25—30. 
At Grimsey the percentage of calm is lowest, on an average about 
10, 4—6 in winter, 16—19 in summer. East and West Iceland show 
somewhat similar conditions, though in winter the percentage is 
higher, about 10. 
The number of stormy days is closely correlated to this (see 
table 1). It applies to all parts of the country that the number is 
highest in winter, lowest in summer. It is, however, very variable. 
It storms most frequently in the south-west and south, Thus Stykkis- 
hölmur has, on an average, 50 stormy days per annum, the Vestmanna- 
eyjar 25. The number is considerably less for the north and east. 
Grimsey has 11, Berufjérdur only 8 stormy days annually. 
