Where’s The Warming? April In Tokyo Hasn’t Warmed In 35 Years…Hachijo-jima Island In 80 Years!

Charts by Tony Heller’s wife, Kirye

The Japan Meteorological Agency (JMA) has released the mean temperature data for April, 2023, for Tokyo and its island in the Pacific: Hachijō-jima.

April is the big month of spring, and warming would tell us that this month ought to be getting colder due to more CO2 in the atmosphere. But the data doesn’t show that.

Here’s the April mean temperature data for the city of Tokyo since 1988:

The April, 2023, mean temperature for Tokyo was a warm 16.3°C, but the trend for the least 35 years still shows no warming.  Data source: JMA.

 Indeed April mean temperatures for the city of Tokyo hasn’t warmed since James Hansen warned of catastrophic global warming before Congress.


April mean temperatures of Tokyo’s island of Hachijō-jima  (located in the Pacific Ocean 287 kilometers south of Tokyo) going back to 1944. The island is rural and free of the urban heat island (UHI) effects.

Data source: JMA.

Here we see that Hachijo-jima’s April mean temperature hasn’t risen in some 80 years! We’ve provided the links so readers can check the data themselves.

Warming little to do with CO2

If we go back to the time since temperature recording began, it’s true that both locations have warmed. Yet if we compare mean daily of  maximum temperature of (urban) Tokyo’s rate to rural Hachijō-jima, we see a glaring urban heat island (UHI) difference:

Data source: JMA

While mean daily maximum temperature in rural Hachijo-jima has risen only very modestly, the rise has been much greater in urban Tokyo, especially over the most recent decades.

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