Cloud Cover

Landscapes are viewed in a variety of weather conditions – bright and sunny, overcast, rainy, foggy, etc. and the weather conditions are likely to affect the enjoyment of the scene. The sky generally comprises a substantial area of a scene, and it is unrealistic to assume it has no influence on preferences. Lighting or cloud features can generate interest in an otherwise mediocre scene and can enhance colors and the clarity of the view. Mist, on the other hand, can engender a sense of mystery that the Kaplans propose to be an important factor in preferences. In flat terrain, the sky’s features tend to be more noticeable than in hilly or mountainous landscapes. 

Studies of cloud cover by Dr A. Lothian

The effect of cloud cover on preferences was assessed in Lothian, 2000. Score 1 represented complete cloud cover with the scene in shadow through to Score 5 with no clouds being present. There were no score 1 scenes but the mean ratings of the other scores are shown in Table 1. Cloud cover can lower preference ratings by up to 1.2 rating units or by nearly 20%.

Table 1 Effect of cloud cover on ratings

Table 1Lothian, 2000. Note: Score 1 = heavy cloud cover through to 5 = no cloud cover. No score 1’s.

The ratings decrease with increasing cloudiness. However, preferences peak at the score 4, i.e. some clouds present, and then taper off slightly at score 5, the cloud-free score. Based on the trend line, the algorithm predicts that score 5 would be 6.55, which is 10% higher than that which occurred. The reduction in score 5 ratings suggests that respondents prefer the presence of at least a few clouds in scenes as this might provide better perspective to the scene, or for the form of the clouds themselves. Whatever the reason, the findings indicate that while the cloud-free scenes rate high, a few clouds in the scene actually enhances preferences.

In the study of the Lake District (Lothian, 2013b), despite the heavy cloud cover, the presence of snow lifted landscape preferences by an average of 6% (Figure 1).

Lakes 8 40CScene with snow rated 7.30

Lakes 7 39CSame scene without snow 6.29
Lothian, 2013b      Figure 1 Influence of the presence of snow on landscape preferences, Lake District, UK

Other studies of cloud cover

Several other studies have examined the influence of the weather conditions on landscape preferences. Anderson et al (1976) described aspects of a major landscape study in Connecticut that included a cloud cover index (the proportion of sky covered by clouds) and an atmospheric clarity index (the amount of haze, smog, etc. in the scenes). Scenic resource values (SRV) of 1.9 and 1.5, respectively, were obtained for the two indexes, compared with 1.09 for land use diversity, 5.6 for a naturalness index and 2.0 for a height contrast. The two indexes were correlated with other features giving a correlation of –0.55 for the cloud index with the SRV while the atmospheric clarity correlation with SRV was 0.3. Both were low, and their elimination had little effect on the regression strength.

Arthur (1977) examined the scenic beauty of forest environments and included measurements of clouds. She found that most observers responded favorably to clouds.

The US 1977 Clean Air Act provides for the detectability of air pollution-caused visibility impairment in certain National Parks and Wilderness areas and effect of this on the visitor’s visual experience. Treiman et al, (1979) showed photographs of the plumes of coal-fired power plants in Utah to respondents and found that clear conditions were preferred to any of the hazy conditions caused by the power plants, and that this impact on visibility ranked 16th out of 26 impacts listed of developments in the region.

Parsons & Daniel (1988) also tested the effects of pollution on visibility and found that those who rated visual air quality for repeated samples of a single vista were most sensitive to changes in atmospheric visibility. Subjects who rated a mixture of different vistas for scenic beauty were least sensitive to visibility changes. Lighting conditions and the composition of the particular vista being viewed also proved to have substantial influence on perceptual ratings.

Hammitt et al, (1994) assessed visual preferences along the Blue Ridge Parkway in the Appalachian Mountains, landscapes with thick vegetation and rolling ridges. They found the area of sky in a scene was the most important predictor, though negative. Their interpretation was that the area of sky is a surrogate for other features, specifically the absence of attractive features such as ridges, rolling plateau and water. Although they suggest that the lack of visual complexity and involvement (in Kaplans’ terms) of the sky support their hypothesis, it does not appear to provide sufficient explanation. The absence of other features is not something that observers would generally notice.

Hammitt et al noted in passing that the area has considerable haze in summer when the photographs were taken and by reducing the comprehension of the landscape, its value is diminished. This is supported by Herzog & Bosley (1992) who suggested that:

“mistiness in a mountain setting reduces both tranquillity and preference but the reduction in preference is greater… Mist reduces the ability to comprehend an environment, and in the Kaplans’ scheme any such reduction would be especially damaging to preferences.”

Mist and haze have a similar effect of reducing the clarity of the scene and its comprehension.

US 2Mist can add mystery to the scene. Glacier National Park, Montana, United States

In their study of the landscape encountered while hiking, Hull & Stewart (1995) found that clouds comprised only about 0.9% of the view, a surprisingly low figure (compared with 23.8% for ground, 14% for vegetation and 20% for mountains and valley).

Wales 1Welsh beach at Borth

Morgan (1999) found that scoring was affected by cloud cover and applied corrections to aesthetic judgements to take account of the weather for scenes of Welsh beaches, commonly viewed through rain or under heavy cloud. The mean corrections from three groups of judges are in Table 2. He also found the correction for broken cloud to be not as severe as for overcast conditions.

Table 2 Corrections to aesthetic judgements of Welsh beaches based on weather conditions

Table 2Morgan, 1999. Rating scale 0 – 20.

In Holland, Buete & Kort (2013) investigated how overcast and lighting conditions affect aesthetic preferences in urban and natural environments (Table 3). The difference between sunny and overcast conditions was as much as 11% for the natural environment and 8.6% for the urban environment. While in dark conditions the difference between sunny and overcast was nearly 13%, for light conditions it was less than 5%. These figures indicate the important influence of light, sunny conditions on aesthetic preferences.

Table 3 Effects of environment, weather type, and brightness on aesthetic preferences

Table 3Buete & Kort, 2013. 7 pt scale

In China, Wu (2013) measured the value of dust (i.e. smoke, dust and dirt in the air) detainment provided by the Hangzhou urban scenic forest and found that although it rose from 8.74 m yuan (US$1.43 m) in 1995 to 9.975 m yuan (US$1.63 m) in 2004, in 2009 it had decreased to 9.924 m yuan (US$1.62 m).

In a study to specifically examine the influence of weather on landscape preferences, White et al, (2014) used scenes of urban, rural and natural areas, half the scenes being of fine weather conditions while the other half were in inclement conditions. Overall, preferences were higher for the fine weather, 5.96 vs 5.42 (10 pt scale). However, the difference was minimal for urbanscapes, greater for rural landscapes, and greatest for waterscapes – 16% difference between fine and inclement weather (Table 4, see also Figure 44).

Table 4 Influence of weather on preferences (10 pt scale)

Table 4White et al, 2014

Cloud cover summary

In summary, it is evident that heavy overcast conditions which prevent the sun from reaching the landscape, reduce ratings of that landscape by as much as 10 – 20%. The effect is greater in natural and rural areas than in urban areas. It is also evident that a few clouds in the scene can lift ratings slightly and so can snow in certain situations. The sky plays literally a backdrop role in landscapes and is generally disassociated from the landscape itself.