When it rains in San Francisco...

a lot of water comes crashing down out of the sky.

It is an amazing thing. But just how much water is it?

  • How to use this page:
  • Figure out how much it has rained today and then look up in the charts how much water has fallen and what this would mean if rain was different (if you want to be exact, you might want to get out some paper and a pen or a calculator).
  • Try and keep all of this in mind when you get wet.
  • Most importantly: think of other things that rain could be and tell us about them so that we can add them to the list.
  • Where do these numbers come from?


  • How much water pours on top of San Francisco when it rains?

    in. of rain cm of rain

    liters of water

    gallons of water

    individual raindrops

    0.1 0.3 300 million

    80 million

    4 trillion

    0.2 0.5 600 million

    160 million

    8 trillion

    0.5 1.3 1.5 billion

    400 million

    20 trillion

    1 2.5 3 billion

    800 million

    40 trillion

    2 5.1 6 billion

    1.6 billion

    80 trillion

    on an average day when it rains in SF

    0.3 0.8 968 million

    250 million

    13 trillion

    the entire average rainy season

    21.5 54.6 65 billion

    17 billion

    860 trillion

     

    If you stacked all this water on top of a football field, how tall would the water be?

    in. of rain

    yards

    miles

    0.1

    70

     
    0.2

    130

     
    0.5

    330

     
    1

    660

     
    2

    1,320

     

    on an average day when it rains in SF

    0.3

    210

     

    the entire average rainy season

    21.5

    14,230

    7 miles

    what I would like to know is: what is the volume of the Transamerica building? How many Transamerica buildings made out of water burst over San Francisco when it rains?

     

    What if it rained wine? How drunk would everybody get?

    in. of rain

    glasses of wine

    glasses of wine per person on the Planet

     est. blood alchohol of everyone on the Planet

    0.1

    2 billion

    0.3

     0.01

    0.2

    4 billion

    0.7

     0.02

    0.5

    10 billion

    1.7

     0.05

    1

    20 billion

    3.5

     *0.11

    2

    41 billion

    6.9

     *0.21

    on an average day when it rains in SF

    0.3

    6.5 billion

    1.1

     0.03

    the entire average rainy season

    21.5

    440 billion

     

     

    * definitely not safe to drive!

    what I would like to know is: how many olives does California produce in a year? What about the whole world? If it rained martinis (also about 5 oz. each) would there be enough olives for all of them?

     

    What if it rained money? How much cash would be falling on our heads if every raindrop were a penny?

    in. of rain

    total amt of money

    per person in San Francisco

    per person on Planet

    0.1

    $40 billion

    $53,798.08

    $6.84

    0.2

    80 billion

    $107,596.16

    $13.68

    0.5

    200 billion

    $268,990.41

    $34.19

    1

    400 billion

    $537,980.82

    $68.39

    2

    800 billion

    $1,075,961.64

    $136.78

    on an average day when it rains in SF

    0.3

    130 billion

    $172,153.86

    $21.88

    the entire average rainy season

    21.5

    8.7 trillion

    $11,566,587.61

    $1,470.33

     

    What if rain were caused by people in the sky peeing on us?

    in. of rain

    people who would have to pee on San Francisco

    # of times everyone in SF would have to pee

    0.1

    1 billion

    1,345

    0.2

    2 billion

    2,690

    0.5

    5 billion

    6,725

    1

    10 billion

    13,450

    2

    20 billion

    26,899

    on an average day when it rains in SF

    0.3

    3.2 billion

    4,304

    the entire average rainy season

    21.5

    220 billion

    289,165

     

    What if it was just one really big person? (peeing just once)

    in. of rain

    this person would weigh how many tons?

    and be this many miles tall

    0.1

    75 million

    960 thousand

    0.2

    150 million

    2 million

    0.5

    380 million

    5 million

    1

    760 million

    10 million

    2

    1.5 billion

    20 million

    on an average day when it rains in SF

    0.3

    240 million

    3 million

    what I want to know is: how big is the sun? Is a person who is this tall bigger than the sun?

     

    What if it rained milk? How many cows would it take to make all of this milk?

    in. of rain

    # of cows

    0.1

    13 million

    0.2

    25 million

    0.5

    63 million

    1

    127 million

    2

    254 million

    on an average day when it rains in SF

    0.3

    41 million

    there are approximately 800,000 cows in California

    what I would like to know is: how much cheese can you get from a gallon of milk? If we could switch back and forth between it raining milk and raining wine, would we be able to get enough to have a global wine and cheese party?

     

    What if it was just one really big cow (like a Holstein)?

    in. of rain

    the cow would weigh
    (tons)

    0.1

    8 million

    0.2

    16 million

    0.5

    41 million

    1

    82 million

    2

    165 million

    on an average day when it rains in SF

    0.3

    26 million

     

    If you made rain by slicing a chunk of water out of the ocean (all the way down to the bottom) and then carried it through the air and dumped it on San Francisco, how big a chunk would you need to slice out?

    in. of rain

    a square with sides this big (meters)

    0.1 9
    0.2 13
    0.5 20
    1 28
    2 40

    on an average day when it rains in SF

    0.3 16

    the entire average rainy season

     21.5  131

     

    When it rains, a lot of water falls on our heads. But just what fraction of all the water on the planet is this?

    in. of rain

    fraction of all the water

    0.1 0.2 trillionths
    0.2 0.4 trillionths
    0.5 1 trillionth
    1 2 trillionths
    2 4 trillionths

    on an average day when it rains in SF

    0.3 0.7 trillionths

    the entire average rainy season

     21.5 46 trillionths 

    A drop in the bucket.


    What would you like to know? (send your suggestions for other things which should be on this page)


    Where do these numbers come from?


    Four links which you might find useful:


    This page created 11/28/1997
    last added to on 12/05/1998


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