In higher primates there are two anatomically distinct visual pathways, one specialized for blue-yellow and the other for red-green information. The perception of colour mediated by these pathways is known to be distorted in the peripheral visual field. There are, however, four so-called unique hues, ”each of which shows no perceptual similarity to any of the others” [1], that do not vary across the visual field. On a colour plane, daylight can be represented by the ‘Planckian locus’ that extends from ice blue (northern morning sky) to deep orangey red (evening-like sky). In this study we set out to investigate the relationship between the stability of perceived colours across the human retina, unique hues, and the different phases of daylight. 38 colour normal human observers performed an asymmetric colour-matching task in the nasal visual field, where the chromaticity of a para-foveal (1° eccentricity) 1° diameter probe spot was matched, in terms of hue and saturation, with a peripherally viewed test spot at 18o eccentricity. 24 different colours, forming a circle in CIE 1931 xy colour space, were tested. Unique hues were identified using a 4 Alternative Forced Choice (4AFC) hue-naming paradigm in which a coloured spot was identified as only red, blue, green or yellow. The mean of the maxima of the naming functions defined the position of the unique hues in colour space [2]. In the matching task, the observers’ performance was almost perfect in the vicinity of the Planckian locus, that is, in the blue and yellow regions of colour space. For regions more remote from the phases of daylight, characteristic distortions in terms of hue and saturation were evident, resulting in the colour circle becoming elongated along the red-green axis. In the additional 4AFC task, the unique blue and yellow were virtually coincident with the Planckian Locus. The results suggest that colour perception mediated by the phylogenetically older (blue-yellow) colour pathway [3] has been strongly influenced by the different phases of daylight. It has evolved to be more stable in the near peripheral visual field than the more recent red-green mechanism.