Summer in Japan: heat, humidity, and latitude

I enjoyed a terrific International Turfgrass Society meeting in Japan. The heat and humidity came up in conversations multiple times, usually something like this: “It’s really hot and humid here, more so than I expected.”

Japan does have hot and humid summers, and I suggest the “growing bentgrass in tropical heat” post for an overview of the temperatures.¹

What about the frequent surprise, though, at how hot it is? If you are anything like me, you would be familiar with weather in the Pacific Northwest, with the temperatures along the coasts of Oregon, Washington, and southern British Columbia. And looking at a globe, or thinking about where Japan is, you might consider Japan to be somewhat opposite from those shores, and thus to have a similar temperature pattern.

One can find temperatures like the Pacific Northwest—the golf course above at a high elevation does have a lot of cool-season grass, albeit with a substantial base of noshiba (Zoysia japonica). On a foggy day up there, one could feel that one was in the Pacific Northwest.

But that’s not actually where Japan is, in terms of latitude. Not even close. A much better comparison is the Florida, Georgia, and Carolina coastal regions. This map shows East Asia (China, Korea, and Japan) with latitude lines prominently marked, and then aligns the east coast of North America with those same lines of latitude.

Tokyo has a similar latitude to Raleigh, NC.

Osaka (and nearby Kyoto) are farther south than Charlotte, NC.

Going from Fukuoka south to Naha is like going from Myrtle Beach down to Ft. Lauderdale.

If we add the west coast of North America, we see that the latitude from Japan’s major population centers is in the San Luis Obispo down to San Diego region. Not Oregon and Washington.

If you are interested in this further, the JMA have an informative Climate of Japan page that includes maps, general information, and a lot of statistics.