Is there a certain time of year when they appear more colorful?

I dont think time of year would make a difference as time of day.

After a rain storm while they are still wet. Colors are deeper then.

Sunset or sunrise us pretty cool

Best when sun is shining on them sunrise or sunset.

Agreed, Dawn or dusk would add to the color. And it does get hot in the summer!

This is also a good time of year to go because it's not too hot