Throughout the day the sun constantly changes position.
In photographic terms this movement is more than one from east to west: any change in the sun will produce a different effect on any landscape.
In the early morning and evening the sun will be quite low; the shadows it casts will be long and dramatic.
In winter the sun will be lower still and these shadows will be even more exaggerated.
At midday the sun will be high and the shadows cast will be shorter.
In some of the cases this can lead to flat and featureless shots, so care must be taken at this time of day.
In colour photography there is contrast between different colours as well as different tones.
The other factor to consider is that the light cast by the sun in the early morning and late afternoon will have a warmer tone than that of midday light, so pictures taken at these times will appear redder or more orange than those taken in the middle of the day.
It is well worth making the effort to get up early, before the sun rises, to be in position to capture the quality of light as dawn breaks.
A little research beforehand will show where the sun will be and what it will fall on, depending on the time of year.
Early and late rays of sunlight can illuminate an isolated area of a landscape in much the same way as a giant spotlight trained on the scene.