Meteorological and biometeorological conditions during the warm seasons (June– September) of 1979–2008 are described for the Hornsund area, Spitsbergen. The measure− ments were taken at four sites: at Hornsund, at the Hans Glacier (at its equilibrium line and in the firn section) and at the summit of Fugleberget. The variation of meteorological and biometeorological conditions was analysed in relation to altitude, distance from the sea and the ground type. In warm seasons, the air temperature at Hornsund was 2.2°C higher on aver− age than at the Hans Glacier (central section) and by 2.8°C than at the Hans Glacier (firn sec− tion) and at Fugleberget. The average wind speed recorded at Hornsund was higher (0.6ms−1) than at the Hans Glacier and lower (0.9ms−1) than at Fugleberget. Four biometeorological in− dices were used: wind chill index (WCI), predicted insulation of clothing (Iclp), cooling power (H) and subjective temperature index (STI). The strongest thermal stimuli were ob− served on the Hans Glacier and in the upper mountain areas. The study has found a consider− able degree of spatial variation between the meteorological elements investigated and the biometeorological indices in the Hornsund area. The impact of atmospheric circulation on meteorological elements and biometeorological indices is also presented. The mildest bio− meteorological conditions of the warm season found at Hornsund were associated with air masses arriving from the southwest and west.

The article presents the biometeorological impact of thermal and humidity conditions on the human body in the Hornsund area in the southern Spitsbergen, Svalbard. This was determined based on diurnal air temperature range, the day-to-day variation in average diurnal air temperature and the average diurnal relative humidity. The temporal variability of thermal and humidity biometeorological stimuli in Hornsund was examined for the period 01.11.1978–31.12.2017. A lessening of biometeorological impact was found in the southern Spitsbergen region, including a statistically significant negative trend in strongly- and severely-felt stimuli (according to diurnal air temperature range), and in significant and severe stimuli (according to day-to-day variation in average diurnal air temperature). A non-significant positive trend was observed in the number of days of relative humidity with humid and very humid air. To analyse the spatial variability of the stimuli around the Hornsund fjord, data were used from seven year-round measuring stations for the period 01.07.2014–31.06.2015. The most unfavourable conditions were found on the Hans Glacier, on the summit of Fugleberget and inside the fjord. The paper presents the role of atmospheric circulation on thermal and humidity stimuli. In the Hornsund region, the highest probability of unfavourable sensible temperatures for humans occurring during the year was mostly in winter and early spring. This was related to the advection of air masses from the north-east sector, regardless of baric regime type. It was found that very humid air (> 85%) flowed over Hornsund for practically the entire year from the S–SW as part of both cyclonic and anti-cyclonic systems.