A riddle while you wait

Hi! This is Mary Anne.
I'm going to try to post every day while we're on the sabbatical about the adventures we have. In the meantime, here is a riddle I made up two years ago.

I'm giant at times,

and small at times, too.

Always one color,

not brown and not blue.

I'm strong in the sun,

and weak in the rain,

sometimes I've a binky,

and sometimes a cane.

Sometimes I am old,

and sometimes I'm new,

not yellow or red,

not green and not blue,

So guess what I am,

and guess me right now,

The answer is close,

and soon you'll know how.

Happy Guessing!