If you go back to the Greek roots of the word, Photography means “drawing with light” (phos = light, graphe = drawing). Therefore, the kind of light you have when taking a picture is very important. There is the so called ‘Golden Light’ which is about 30min to 1 hour after sunrise or before sunset. 10am – 2pm (or longer in the Summer) is considered the worst light, because it is very harsh. This is somewhat correct if you consider just landscape photography.
In reality, there is no ‘bad light’. One needs to change the kind of image one plans on taking. Let’s go through the day and look at the kind of images one can take:
Time before sunrise: the sky or clouds can have incredible colors; mountaintops are already sunlit while everything else is in shadow; great for silhouettes against the eastern sky.
Sunrise + about 1 hour: soft light, great for regular landscapes and wildlife
Midday (10am – 2/4pm): great if you are in a forest or among trees; use the light reflected from other things in the sun to gain light on items in the shadow; reflections on water of sunlit foliage
Sunset – about 1 hour: soft light, great for landscapes and wildlife
Time after sunset: blues and mauves in the sky and clouds; silhouettes against the western sky
Overcast, cloudy sky: This provides nice, even light, which is great for things in the ‘shade. It is important to remember to keep the sky out of the image.
Moon rise, Moon set: check the times. A moon rise is best a day or two before the full moon. This still gives you some light. Along the same line, a moon set is best a day or two after the full moon.