North America-November

North America-November
Army Map Service, 1943
Climate Zone Map
1: 20,000,000

Hi everyone, 

I hope everyone is enjoying this beautiful but strange weather outside! It’s been so really warm lately during the daytime that it does not feel like November at all. Experiencing this warm November weather, I would like to highlight this Climate Zone Map “North America-November” made by Army Map Service and bring you all to see what the climate was like in the middle of last century. 

In around 1943 and 1944, AMS made a series of climate zone maps of regions across the world. These maps are classified based on continents and months. They are not commercial maps made for the public but military maps for use by the War and Navy Department Agencies.

Made in Lambert’s azimuthal equal-area projection, this map shows the temperature and humidity distributions of North America in November around 80 years ago. The Lambert azimuthal equal-area projection, often used in the mapping of large landmasses or continents, allows the map to maintain land features at their true relative sizes. In the lower-left corner, the map legend presents a table of symbols showing that the symbology is determined by both temperature and humidity. While the temperature is listed in Fahrenheit, there is a conversion graph between Fahrenheit and Celsius on the right side of the table. The Wind Chill Temperature, as listed for climate zones in the north of Canada and Greenland, is defined only for temperatures at or below 50°F and wind speeds above 3 mph. 

As the map shows, the average temperature of the Northeast US in November should be around 32°F to 50°F, which is lower than the average of today. There are many reasons–such as global warming or La Niña–that may have influenced the warm temperature today. What are some other reasons that you could think of?

Have a great week!

Yidan Xu ’24