When I first began painting
en plein air about 10 years ago I was totally overwhelmed by the sheer intensity of sunlight and equally underwhelmed by the monotony of an overcast day.
Here in New England we have 3 types of summer day:
Sunny, dry and gorgeous: rare, but loved by all.
Hazy, hot and humid: common and generally tolerated, as we can't control the weather (yet).
Pouring rain: often times welcomed as that usually signals a turn in the weather back to drier sunnier days.
When I began painting outside I just could not seem to make a "good" painting. They were either dull and lifeless, washed out or dark and morbid.
Older and wiser artists pointed out that my paintings were always comprised of a single value family. Either all in the middle range or all in the high key range etc. They told me what I lacked was value contrast.
Bah Humbug to that I grumbled. I was a colorist (at that point in my career) and didn't give a fig about values.
But in the end it turns out they were right. It is value contrast that creates "pop" in a painting, it's what draws a viewer from across a room, it's what gets a judge's attention, it's what creates a convincing sense of form and the feeling of sunlight.
Value does all the work, but color gets all the credit. Just another one of those unfair things in life. Actually, the reason for that is because it's much easier to identify the color and much harder to identify the value of a thing. That's partly due to the characteristics of color,(hue, value, intensity, temperature) intensity being the thing that will throw you off most easily.
Don't let color bewitch you, and don't let overcast days or bleaching sunlight trick you into creating boring paintings.
Read master painter Charles Sovek's explanation of
Basic Lighting Conditions and
Different Kinds of Light .