The Earth is warming and disturbing the balance of the seasons. Data makes it clear that summers are expanding while winters are substantially shortening. I recently completed an analysis that examined the hottest and coldest 90 days of the year, approximating summer and winter, over the past two 30-year periods, 1960-1989 and 1990-2019. What I learned was that the hottest temperatures that defined the first 30 years expanded over additional days in the most recent 30 years. Conversely, the coldest temperatures defining the preceding 30 years contracted. In other words, most locations globally, including in the United States and Canada, have seen their summer season lengthen and the winter season shrink.
Longer summers
The vast majority of 6,000 weather stations analyzed globally now experience a longer summer compared with the previous 30-year reference period.
In the United States and Canada, summer has expanded by an average of one week.
The lengthiest increases in summer conditions, colored in orange and red, have occurred over the southern United States, as well as in eastern and western Canada.