Contrasting dark storm cell clouds overtaking nice blue fluffy clouds.
As they pass the thunder and lightning is spectacular, then the rain comes. It rains for about 2-6 minutes just enough to soak everything, and then it moves away allowing the sunlight to return. In its wake though the temperature drops 5-10 degrees and it stays cool for a few days until the the heat returns, then the whole process starts over again.
I kid you not, it has been doing this for 4 months now!