Speaking of Weather

Two days ago, it was sunny and 78 degrees. I had all the windows in my house open for like 4 days straight. Spring fever was setting in. I even broke out the flip-flops.

Today, the high did not even reach 40 degrees, and lows in the 20's tonight. There is even a chance of sleet and snow tonight and tomorrow. The windows have all been closed, and there's been a fire burning my fireplace since this morning.

What is going on here?