Climate Change Giving Meteorologists a Hard Time Mapping Extreme Heat


Warming trends around the globe due to global climate change are upending weather maps, by being so hot that meteorologists are running out of colors to show areas of extreme heat.

Last week, Arizona saw near-record high temperatures at 119°F (48°C). The temperatures were so high that people were receiving burns from concrete and other surfaces outdoors. The projection map of the Phoenix metropolitan area used a bright green to denote the areas with hottest temperatures.


Mark Torregrossa, a meteorologist commented on the seemingly incongruous use of green for super hot areas.

“All of the orange and red shades are used. The next stage of heat, depicted by what I would call violet colors, is blown right through on this temperature map. I guess finally you get so hot you turn green,” writes Torregrossa in an article for Michigan news channel MLive.

Torregrossa says that while traditionally fire-y colors like oranges and reds are used to show warm weather, but the near-record temperatures sweeping across Arizona, California and Nevada right now have smashed right through the “color box”. A similar problem was faced by meteorologists in Australia during an intense heatwave back in 2013, which the country’s weather experts decided to get around by using neon purple and pink in their spectrum for areas around 125°–129°F (52°–54°C) in temperature.

There are no standardized colors for use on weather maps, regional weather graphics providers must establish their own logical color scales. For instance, the Weather Channel uses a 17-color scale where light yellow is used for the hottest temperatures. If the heat waves continue to be near record-breaking levels this summer, expect to be seeing many more of these unusual colors on your local weather forecast.