28 October, 2014

What is summer?

I'm sitting in air conditioning. Yesterday it reached 40 degrees Celsius here and today was forecast to be the similar. When I rode to school with the boys this morning it was about 34 degrees.

This is spring in Brisbane. Sometimes people I meet in Japan ask about the climate where we come from. "About five months of summer," often shocks people.  Tokyo's summer isn't as long, but it is terribly hot and humid, even at night.

The heat in Tokyo ramps up at the beginning of July and sticks around, generally until sometime in September. Compared to Brisbane, where we're getting already 40+C temperatures in October and could be getting them until March, Tokyo has a short summer!  But it's brutal. Some of that is because with 30 million people occupying the Kanto plain, an urban heat island has been created.
An urban heat island (UHI) is a metropolitan area that is significantly warmer than its surrounding rural areasdue to human activities. The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon.[1] The temperature difference usually is larger at night than during the day, and is most apparent when winds are weak. UHI is most noticeable during the summer and winter. The main cause of the urban heat island effect is from the modification of land surfaces, which use materials that effectively store short-wave radiation. (From Wikipedia http://en.wikipedia.org/wiki/Urban_heat_island.)
In Tokyo, average maximums exceed 25 degrees for only four months of the year (June to September). In Ipswich (just west of Brisbane, where we're living this year), average maximum temperatures exceed 25 degrees eight months of the year! 

But the real killers in Tokyo are the humidity and night-time temperatures. Humidity in Tokyo sits at around 70% throughout summer. Night temperatures in July and August average 23-24.5C. Average night temperatures in Ipswich never make it above 20 and the humidity stays around 43-54%.

The other thing that isn't so easily reflected in statistics is that Toyko's heat, when it comes, tends to stick around at a high level, like a two-month heat wave. Brisbane/Ipswich's heat tends to come in shorter waves. So a few super hot days will be generally be followed with some cooler ones.

A while ago I mentioned on FB that I prefer a Brisbane/Ipswich summer to a Tokyo one and someone suggested that I'd forgotten how brutal Ipswich summers can be. 

But I don't take either summers lightly. It is so easy to get dehydrated in Australia's dry heat. Tokyo's heat saps you tremendously, especially when you're not able to sleep in air conditioning.

I was going to write a post about spring in Australia, but with the temps what they are today, I think I'll just go and sit at the water cooler and wait until it feels more spring-like again!

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