We have a Sunday morning family tradition in which my daughter reads the weather page from the newspaper while we are driving in the car. The rest of the family guesses the previous day’s high and low temperatures for the state and the nation along with where these extreme temperatures occurred. As the seasons change, we change the location of our guesses and the temperatures themselves. Curious about the spatial pattern of these high and low temperatures, I created a geodatabase of the January 2009 extremes, other data, and a lesson in the ArcLessons library, ready for you to analyze it, on: http://edcommunity.esri.com/arclessons/lesson.cfm?id=408

Does this pattern of high and low extremes, symbolized by red H ovals and blue L ovals, surprise you? What difference does proximity to the ocean have on extremes during different seasons of the year? Why?

Why are the coldest temperatures in Alaska not in the far north, but in the interior? Why did they occur not in the highest elevations, but in the lowlands?

What and where was the highest temperature in January in the USA? Did temperatures warm up as January progressed? Did any city over 100,000 people experience an extreme? Can you find any patterns or clustering in the data? Can you discover heat waves or cold snaps that affected multiple cities?

Did Hawaii experience temperature extremes? Do you think Hawaii will set temperature records during summer months, or are the temperature records here set only in the winter? Why? Is there a difference in the climate between the cities in Texas, Florida, and Hawaii where the hot temperatures occurred in January? If so, what is it, and why do these differences occur?

Skills highlighted in this lesson include analyzing spatial patterns and processes within a GIS framework, investigating temperature extremes and their relationship to latitude and altitude, tabular queries, labeling features, and selecting map elements. Data layers include January 2009 extreme temperatures, US states, elevations in nine categories, cities, and Canada and Mexico’s provinces and states.

- Joseph Kerski, ESRI Education Manager