Are the Seasons Shifting ?

Legend

Monthly Average Temperatures in Celsius for the Control Period

Monthly Average Temperatures in Celsius for the Experimental Period

Sesonal Range for the Control Period1

Sesonal Range for the Experimental Period2

1Start and end dates are based on the meteorological definition of the season

2Start and end dates are based on when the 9-day average matches the control period

Season Start

Spring 0 0/0 0/0
Summer 0 0/0 0/0
Fall 0 0/0 0/0
Winter 0 0/0 0/0

Season End

Spring 0 0/0 0/0
Summer 0 0/0 0/0
Fall 0 0/0 0/0
Winter 0 0/0 0/0

Settings

1885 - 1904 and 1970 - 1989 monthly averages in the continental US

0F

Data source: NOAA 1981-2010 Climate Normals - Global Historical Climatology Network (GHCN) Daily Normals

Start of spring shifted by 0 days

Start of fall shifted by 0 days

Start of summer shifted by 0 days

Start of winter shifted by 0 days

What is the effect of climate change on the meteorological seasons?

Although it is clear that temperatures all over the globe are rising, this visualization tries to illustrate the effects of such a rise seasonal weather for the continental US. Shrinking winters and longer summers are apparent in the Southwest and Ohio Valley, while other climate regions such as the Northern Rockies and Plains seems to suffer from the opposite effect.

As you explore this interactive visualization, try to formulate a hypothesis to explain different season patterns you may notice across different regions and range periods.

Methodology

This visualization uses a large dataset of over 85,000 weather stations obtained from the NOAA 1981-2010 Climate Normals page. For performance, the minimum and maximum daily temperatures were converted into daily averages and those were aggregated by U.S. state.

To find the seasonal shift, a 9-day average temperature is calculated for the meteorological season start/end for period 1. Then, we search for a similar 9-day average (higher or lower, depending on the season) on period 2, from the middle of the previous season to the middle of the next one. Once this day is found, we mark it as the new start/end for that season.

Climate Regions

States