Since the "elevated" (by mountains) horizon was taken into account at the Kredarica station which is, in the time of the low position of the sun, in the shadow behind the Triglav ridge (Klimatografija..., 1991, 3), more solar hours were ascribed to it than it had in fact. However, because the radiation energy is low then (see Table 3), this correction is irrelevant. Namely, winter insolation energy amounts but to 12% of the annual quantity, and its sum in the ablation season of the glacier (May-September) amounts to 82% (Hočevar et al., 1982).

It is surprising that, in the annual average, Kredarica has less solar hours (1787 hours) than the lower nearby mountains and even the valley station Rateče-Planica (1904 hours). In summer, the difference is above the average (Kredarica - 541 hours, Rateče - 684 hours) and in this season, even the Bohinj basin has more solar hours (Stara Fužina - 582 hours). This difference is mainly caused by mountainous clouds which are, when covering Kredarica, registered as fog, otherwise as cloudiness. The average summer cloudiness at Kredarica is just a little higher (6.4 tenths of the sky) than at Komna (5.8 tenths) or in Stara Fužina (6.3 tenths), but it occurs mostly at the time when the sun provides the greatest quantities of energy, i.e. at noon and in the early afternoon hours.

The duration of insolation is important for the glacier balance, above all in the melting season (May-September). Therefore, only this season is taken into account in the following table.

Table 1 - Hours of insolation and cloudiness from May to September at the Kredarica meteorologic station (1955-1994).

Note: Clear day - when cloudiness is below 2/10 of the sky; cloudy day - above 8/10 of the sky are covered with clouds. Cloudiness is measured in tenths of the sky.

In all months, cloudiness is greater at 2 p.m. than at 7 a.m. or 9 p.m., which is, above all, due to the "cloud cap" above the Triglav ridge.

The glacier receives significantly less hours of insolation and less solar energy than the Kredarica station which is on the top of the ridge. The glacier is periodically shaded by the three nearby elevations. A first one is the Kredarica elevation with the northeast orientation. Its altitude increases in the same direction, i.e. from the contact with the Mali Triglav massif (peak - 2541 in), while the altitude of the glacier decreases in the opposite direction. Therefore, the shadow cast by the ridge is larger on the lower part of the glacier. This is not emphasized enough on the otherwise good sketch of the glacier's shadiness, made by a cartographer Vilko Finžgar (in: Meze, 1955, fig. 25). Between the spring and autumn equinoxes, when the sun rises north from the East, the upper part of the glacier receives rather considerable amount of insolation in the morning because the Triglav ridge runs, together with the north-facing slope, in the SSE-NNW direction (declination from the W-E direction is 20⁰C).

Major shadow is cast by the ridge running between Mali Triglav (2738 m) and Veliki Triglav (2864 m). At noon when in summer the sun reaches its highest position, no shadow falls on the glacier; however, it rapidly spreads in the afternoon hours over its entire upper half (see the above mentioned sketch). Since the glacier's surface is inclined northwards, mainly by 20 to 30⁰C, the angle of incidence of solar rays at noon in summer solstice amounts only to 37-47⁰, and in equinoxes, between 14 and 23⁰. Therefore, the insolation energy is reduced, particularly if albedo is taken into account, although the short-wave diffused radiation is relatively greater in the mountains in the slightly cloudy and foggy conditions. (See the discussion on the impact of climate on the glacier budget between dr. V. Manohin and I. Gams, 1959).

In the afternoon, when the sun is low, the shadow is cast on the glacier also by the ridge oriented from Veliki Triglav towards Kugy's shelf (Kugyjeva polica) on Triglav North Face (Severna Triglavska stena), with the altitude point of 2665 m on more detailed maps. Due to the NNW direction, the evening shadow in spring and autumn spreads over the northwest glacier. The rays of the summer evening sun have a relatively bigger angle of incidence here than on the eastern edge of the glacier (now a scree) which extends upwards to the foot of the Kredarica ridge. In May, Kredarica receives 158 hours of insolation which is slightly more than in September, but the energy of radiation in May (see Table 3) is greater (138 kWh/m²) than in summer months (Hočevar et al., 1982). Since all the snow fallen in May and some of the older snow, too, melts in May -- in the average of the 1954-94 period, the absolute depth of snow cover has already reduced -- it is ranked to the ablation season even though its average temperature is -0.2⁰C, and in 22 days the temperature drops below 0.0⁰C.