Comparing climates

Michael Mace
Fri, 04 Dec 2009 17:42:46 PST
Hi, gang.

I want to introduce you to a handy little online tool:…

This is's vacation planning tool.  It allows you to compare the
climates of any two cities.  You can look at average maximum and minimum
temps and monthly rainfall.  This turns out to be very useful for comparing
the growing conditions in different parts of the world.  A couple of
examples of what I learned:

--Los Angeles, CA and Perth, Australia have almost identical temperature
profiles (offset by six months).  But Perth gets a lot more rain in winter,
and even its summers average half an inch (1.3 cm) of rain a month.  In
contrast, LA has five months in summer that average less than 0.3 inches
(0.75cm) of rain per month.

--Valparaiso, Chile is an eerily close match for San Francisco, CA.  San
Francisco is a little bit wetter.

--I think there are two different types of Mediterranean climate areas.
What I'll call "Moist Mediterranean" includes South Africa, Western and
South Australia, and southern France/Italy/Greece.  They all get a bit of
summer rainfall.  "Dry Mediterranean" includes California, Chile, and parts
of the Middle East (Beirut and Tel Aviv, for example).  They all have long
periods of virtually no rain in summer.

The implication to me is that if I'm growing South African or Australian
plants, I may need to give them a little bit of summer water.

The tool isn't perfect -- not all cities are covered, and many of them don't
have temperature data.  But this is the best online tool I've found for
comparing basic climate details.

San Jose, CA

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