The cause of the persistent warmth has been an unusually active jet stream off of the Pacific Ocean. A west-to-east storm track brought mild air across the country, resulting in above normal temperatures for mostly every state.

La Nina is building in the Pacific Ocean, which is a signal for cool, damp springs.

You can't point to a warm week or month and blame it on global warming.

We had a warm January, just like we had a cold December. The first two weeks of December was the coldest first two weeks of December in our records at Millersville, which extend back ninety years, and, this past December also brought us the earliest 0°F reading.