280 THORODDSEN 



February and in the first half of March - 2 to 4 C., which is 

 only from 1 to 3 colder than the average temperature of the 

 coldest days in Copenhagen; but, on the other hand, the warmest 

 days in Iceland, which occur in the latter half of July and in 



v - 



August have, on an average, a temperature of only from 7 to 10 C. 

 There are, however, numerous oscillations from year to year, mostly 

 during winter, less frequently during summer. The normal tempera- 

 ture is below zero (Celsius) from the last days in November to the 

 first days in April, or even May 1st on Grimsey. Therefore the Ice- 

 landic summer is very unfavourable to plant-life, the temperature 

 being so low during growth-period. The highest mean tempera- 

 tures for any month fall in July and August and even these reach 

 only to 11 12 l /2 C. (Papey 8.5 and 9.6; Vestmannaeyjar 12.7 

 and 12.3) - the temperature of a mild May or cool September in 

 Copenhagen. By exception, on some days, the heat may be very 

 great; the greatest amount of heat registered at Berufjord was 26.3 C.,. 

 on Grimsey 26.2 C., at Stykkisholm 22.9 C., and in the Vestmanna- 

 eyjar 21.2 C. But in the interior of the island in the valleys 

 a higher temperature (27 28 C.) has occasionally been registered. 

 The lowest temperature registered at Berufjord was 23.1, in the 

 Vestmannaeyjar 20.9; at Stykkisholm 26, and on Grimsey 

 30. l At the coast in Iceland the average temperature of the day 

 and night rarely exceeds 15 C., and at Berufjord there occur, as 

 a rule, during the year, only four days with such a temperature, 

 but in Modrudalur six to seven; a fact which shows among other 

 things that the summer temperature is often higher in the interior 

 of the country, while the cold there is also greater during the winter, 

 On ascending to the interior districts the climate is found to be no- 

 longer so decidedly oceanic as along the coasts, and the vegetation 

 also increases in density the further one proceeds upwards, following 

 the valleys. Coppice-woods often thrive at the head of valleys in 

 places where birch -coppices cannot grow out at the coast. The 

 mean temperature of the coldest day and night in Modrudalur 

 was 29 C., at Berufjord 19 C. During the period March 

 6 12, 1892, when the cold was very severe, the mean tempera- 



1 All these figures are those for the cold, drift-ice winter 18801881. But it 

 should be mentioned here that the Grimsey station had no maximum thermo- 

 meter, and that the temperature - 30 C. was one which was registered during 

 the day. In reality the cold had probably been greater, because in the same winter 

 I noted early in the morning of some days, at Modruvellir in Horgardal a tem- 

 perature of - 32 to 36 C. 



