Days can be very gray with those hazy skies that tend to make everything look dull. Most digital cameras have settings to compensate for that. If you are lucky you can also get beautiful sunny blue sky days.
The beauty of digital is that you can see instant results and delete what doesn't work. Just get familiar with the settings of your camera before you go so you know how to change it on the fly.
Not like the old days of SLRs where you had to think about buying filters.