is your town rainy?

August 13th, 2009

Complaining about rain seems to be some kind of ingrained human reflex. But if (almost) everyone is doing it then surely not everyone has a case? Before I moved to the Netherlands I heard people say it rained here all the time. That doesn't agree at all with my observations. But what's a lot? Compared to what?

I know, facts!

The World Weather Information Service has climate information on 1000+ cities around the world. I decided to do a little data mining. All conclusions to follow are based on that data. Just for kicks, I should mention there are very serious methodological problems with this exercise. First of all, they say countries don't necessarily use the same definitions for what's a rainy day or measure precipitation the same way. So you're not really supposed to compare cities. Secondly, when placing cities on a world scale, sampling is everything. And nothing is known about the criteria by which cities are included in the list. We're not gonna let petty details like that stop us, though.

I should also mention that "rain" as used here also includes snow where applicable.

Is it rainy here or what!

So is it rainy here? Let's compare it to the control point: Trondheim. And let's throw in some other data points too, for good measure.

  • Cities with a reputation for rain: Bergen, London, Seattle, some town on the Spanish north coast (found A Coruna on the list).
  • Cities known to be dry: Los Angeles, Zaragoza (turns out to be the driest city in Europe)
  • Other cities: Berlin, Dublin, Milan, Paris, Stockholm

The first number is the total annual precipitation. The second is the number of rainy days.

city            mm/y   days
Bergen          2250   235
A Coruna        1008   171
Seattle          945   122
Milan            943    86
Trondheim        892   216
Amsterdam        780   185
Dublin           733   129
Paris            650   112
London           611   145
Berlin           571   106
Stockholm        539   173
Zaragoza         317    79
Los Angeles      305    27

Bergen's reputation is well justified, it turns out to be the rainiest city in Europe. Rainy London, on the other hand, is a complete myth.

No, not like that, use *all* the facts!

But what do random cities tell us about the big picture? Not much. Let's see how countries place on the overall ranking. Here we see the span they occupy in the list, from the rainiest city on the left to the driest on the right. (Spain refers to mainland Spain.)

rainplot

The Netherlands place smack in the middle. So to say it's a rainy country is an obvious exaggeration, it's pretty much average. The very narrow span is probably due to the small and uniform geography. Norway, on the other hand, is definitely rainy, occupying the space in the rainy portion of the list. Bergen is most rainy, Oslo is least. As for London, it's actually the lower end of the UK span, further diffusing its rainy reputation.

If you like staying dry the very best place to be is Luxor in Egypt, where precipitation is a minuscule 3mm annually. At the other end is Quibdo in Colombia, with an incredible 8m of rainfall and 305 days of rain.

But you didn't...

I know, but this isn't supposed to be comprehensive. If you want to do further work on this data you can get the list I generated:

:: random entries in this category ::

3 Responses to "is your town rainy?"

  1. erik says:

    So Amsterdam is considerably rainier than Seattle, Dublin, A Coruña, Stockholm and London. I think that warrants some complaining.

  2. numerodix says:

    You could be in Bergen...

  3. erik says:

    Granted, that'd be worse. In a variety of different ways, not all related to climate