Brainstorm Answer: Nighttime is the Winter of the Tropics |
 Dave Thurlow, Host |
Hi, I'm Dave Thurlow from the Mount Washington Observatory. On a recent Weather Notebook Brainstorm, I asked what the following statement meant: "Nighttime is the winter of the tropics." What does that mean? Does it have anything to do with weather? Did some writer just want to wax poetic about the tropics and thought up "nighttime is the winter of the tropics?" And just what does 'wax poetic' mean?
Well before we stray too far from what we talk about on The Weather Notebook, here's David Huston from Las Vegas, NV, a listener of affiliate station KUNV:
"In the tropics, there are no major seasonal changes. When they say that 'Nighttime is the winter of the tropics', that is the greatest temperature drop that the tropics see. Hence, the term that they're using it as their winter because their greatest seasonal change they find in the tropics is when the sun goes down at night."
David's right. In the temperate US, temperatures tend to fluctuate from season to season, while in the tropics, the temperatures are consistent year round. For example, let's look at David's hometown of Las Vegas, NV. In January, the average high temperature in Las Vegas is 60 and the low is 29. In May, it's 89 and 52. And in July, the averages are 103 and 68.
Now, let's look at a city in the tropics, like Kisumu, Kenya. The average January high there is 85 degrees and the low is 65 degrees, In May, its 81 and 65. July, it's 80 and 63. As you can tell, the temperature is about the same throughout the year. So, the coldest part of the year in Kisumu, Kenya or any tropical city is going to be at night. And that's why, 'nighttime is the winter of the tropics."
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