Predict Weather With a Cup of Coffee




Introduction: Predict Weather With a Cup of Coffee

About: Mops from sticks and rags. Cheap!

I learned this trick reading Backpacker Magazine years ago while waiting for an air taxi flight into the Nahanni River. It really works.

Make a cup of coffee. I like to add cream and sugar since it makes the bubbles easier to see but black coffee is fine. Hot tea or hot cocoa will work too.

Step 1: Watch the Bubbles

When you pour the coffee into your cup, watch the bubbles.

If the bubbles move to the edge of the cup rather quickly, that's a good sign. Expect clear skies for the next 12 hours.

If the bubbles hang around in the center of the cup, get out your rain gear. You can expect rain in 12 hours.

If the bubbles slowly move to the edge of the cup, you may get a bit of weather, but it should be clearing in a few hours.

If you've managed to make a cup without bubbles, flop a spoonful of coffee back into your cup and make some more bubbles.

Step 2: Theory

The theory behind this trick is that high pressure will push the bubbles to the edge, and high pressure indicates a period of sunny, calm weather. Low pressure won't move the bubbles and low pressure systems typically bring unsettled weather.



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    60 Discussions

    wow this amazing.

    Amazing I gonna try it !

    My mom told me about this about a month ago. The few times I done it, it was right. Crazy how such a little everyday things works :)

    I don't think I want to know what gets predicted when a frog jumps in your coffee. Best just run for the hills. :-)

    Adams had been to The End of Time Restaurant, so he naturally knew all.

    P.S. The coffee trick works best if you can get exactly 42 bubbles ...

    3 replies

    I wonder what the improbability factor of getting exactly 42 bubbles would be?

    Which, of course is 42 x 10^(42/2). The chances of this occurring randomly is, well, pretty Improbable - as a rough Guide.

    How exactly does this work? I drink tea every day and I never noticed this cool trick. I should try it.

    1 reply

    I've been using this method of predicting the weather for about two months now, and it hasn't failed oncen
    It works 100% :)

    1 reply


    On the other hand, I've had a couple of failures since I moved close to the shore of Lake Superior a couple of years ago. Seems like sometimes the predicted rain stays out over the lake and doesn't make it to shore.

    Is there any best temperature of coffee or temperature difference between coffee and air around to perform the observation^
    You're supposed not to stir your coffee, is it ? Just leave it still and observe the phenomena. I don't catch the theory of atmosphere pressure pushing significantly
    on coffee surface, Ok it does but that's sounds like atmosphere blowing more or less in the centre of the cup and why not the reverse , I mean some kind of blow from side to center or the like. What about influence of air % humidity?

    1 reply

    Temperature differences haven't affected my observations I don't think.

    Stirring tends to either move the bubbles to the outside edge or congregate them in the center vortex, so that's a no-no. You do run into problems when the coffee doesn't cooperate and you have to use your spoon to make bubbles. A dip and splash technique usually avoids excessive manual bubble movements.

    Barometric pressure may be affected by humidity, so that could affect the bubble reading. To avoid that you could dispense the coffee into a clear wet bulb I suppose. Don't know, just slinging out ideas, but some of this stuff can make you go psychro (sic) on the meter scale.

    Saw this a few days ago - we've been having an unusual heat spell due to a high pressure front that's moving away.

    So far the predictions of the cup have been ringing true, I drink a lot of coffee...

    The weather report agrees too, so it may be wrong yet, it's not right often...

    I tried this experiment with Vodka but always needed a lot of data so, after a while into my lab time, I didn't care what the weather was...