title banner
weather features homepagewhat is weather?weather forecastingwhat powers the weather?precipitation sectionwind sectionthe changing climate


rain ruler

Measuring Rainfall

Rainfall is usually measured by first collecting it in a rain gauge. These special drums are then used to record the depth of the water inside. Rain gauges are usually about 50 cm tall and are placed on the ground just high enough to avoid splashes. Rain water that is caught in a funnel on top, runs down into a measuring cylinder below – where it can be recorded.
To make your own rain gauge to keep a record of how much rain falls, follow the instructions below.

You will need:

  • a large plastic soft drinks bottle
  • scissors
  • a ruler
  • a waterproof marker pen (or coloured sticky tape)
  • a heavy flower pot
  • a notepad and pencil (to record the results)
cut bottle  

REDBALL With the help of an adult, carefully cut the top off the plastic bottle with the scissors.


REDBALL Turn the top upside down and wedge it in the bottle to form a funnel. (If necessary, use sticky tape to hold the top of the bottle in place).

mark scale on bottle  

REDBALL Using a ruler, measure out a scale (in millimetres) on a piece of paper. Either stick this to the side of the bottle, or use the marker pen to mark out the lines instead. Alternatively, cut the coloured tape into strips and stick them a certain distance apart (eg: 10 mm) up the side of the bottle. Make sure that whatever you use, it is waterproof!

Place gauge in pot  

REDBALL To prevent the rain gauge from blowing over, place it outside in a heavy flowerpot. Alternatively, you could dig a hole in the ground for it to stand in. Make sure the rain gauge is placed in an open area. If it is near any trees or buildings, extra water could drip into it and your measurements will not be accurate.


REDBALL Now you are ready to record how much rainfall is received over a certain time. Check the rain gauge every day, or once a week if you prefer, and record how much water is in the bottle. Use the scale or the marks on the side of the bottle to help you.


Remember, if you are only taking measurements once a week, make sure your rain-gauge does not overflow in between if you get a lot of rain. You could always use a measuring cylinder to store the week’s rain before you measure it.

Plot results


REDBALL Each time you measure the water, plot the results on a graph or in a table. You could print out the table below to help you if it is easier. Make sure you could draw it yourself as well though.

  Week of ..................

Rainfall (mm)

Days of Week Mon Tue Wed Thu Fri Sat Sun

Weekly Rainfall chart



Now you know about rainfall - and how to measure it - let's move on to find out about another form of precipitation - snow.

top of page

previous next