Occasionally the weatherman gets it wrong. You wake up one morning hoping to record several milliliters of rain, but unfortunately, all you find is scorched ground from last week’s hot sun. Once again, the weather reports were inaccurate, and you can’t deal with them anymore.
It happens that rains are sometimes spotty and what you record here is not the same 20 miles away. That’s why you can’t always rely on weather reports, especially if you own a garden or yard. I may sound rancorous, but your plants might just dry up if that is your only source of weather information.
You need to devise your own means. You need to learn how to measure rainfall at home!
If you think this is the way, continue reading along.
How to Measure Rainfall at Home
Step 1: Choosing a Rain gauge
Of course, you need a rain gauge to measure the amount of precipitation in the atmosphere. But which one will you go for? It is possible to build one yourself, but I suggest you get one with accurate calibrations for the sake of precision.
A good rain gauge should measure even the slightest amount of precipitation but not mist or dew. Most are cylindrical and have a funnel at the top for a larger surface area. You need one that comes with a stand so you can set it up anywhere in your garden or yard.
In fact, some rain gauges come with decorative stands to give your garden a more aesthetic look.
Step 2: Choosing Location
Where do you want to place your rain gauge? Most homeowners have them behind their houses, around the porch, and sometimes near trees. All these are wrong locations and will affect the overall accuracy of your measuring instrument.
You should place the rain gauge away from obstacles such as trees and buildings. For instance, if you have a house nearby, ensure the distance from the building to the rain gauge is twice the building’s height. The same applies to trees and any other taller obstacle.
Step 3: Recording and interpreting the Readings
So it rained the previous night, and there is some water in the rain gauge. All you need now is to record and interpret the results. But how do you go about this?
If you observe the water keenly inside the rain gauge, you will notice that it curves inwards, creating a meniscus. Take a book and record the water level on the lower meniscus of the rain gauge, calibrated in millimeters (mm). That is the amount of rainfall for the first day. Do this every day to establish a trend.
If you want to learn more about rainfall measurement, there is a society called CoCoRaHs, which educates the young and old, and the only requirement is your enthusiasm.
See also: What is the best way to collect rainwater without a roof?
Rainfall Measurement Methods
We need rainfall data to plan for agricultural activities, traveling, and general knowledge of how much rainfall we should expect at a given time of the year. That’s brilliant and important too, but there is a need to take precise precipitation measurements for this to happen.
Here are the methods used to measure rainfall;
Method 1: Manual rainfall measurement using a rain gauge
You probably have heard of rain gauges a couple of times and wonder how they work. Well, they are the most available method of rainfall measurement and probably the easiest ones too. All you need is some basic scale reading, and you are good to go.
There are two types of rain gauges,
- The recording type
- And the non-recording type
Recording rain gauges automatically records the amount of rain permanently in a graph giving weathermen cumulative data for a given period. They also indicate the duration and intensity of rainfall every time there is a downpour.
Under the recording type rain gauges, we have three categories;
- A tipping bucket rain gauge
- Weighing bucket rain gauge
- Floating type rain gauge
The other type of rain gauge is the non-recording type, which collects precipitation but does not keep the data. You have to manually record and interpret the results. Most homeowners and institutions use this method since it is cheaper and more effective for small-scale use.
Using a simple rain gauge is the best way to learn how to measure rainfall at home.
Method 2: Rainfall Measurement by Radar
To determine the amount of rainfall over a radius of 50 miles, you will need a network of rain gauges stationed strategically within this radius. Unless several rain gauges of the same type are working concurrently, chances are your data will be botched. More so, using so many rain gauges is quite a tedious task.
That’s why it is best to measure rainfall using radar, especially if you intend to cover a wide radius. Radars are designed to continuously display the distribution of precipitation over a wide area. It is now possible to measure rainfall over the sea and in sparsely populated regions through a radar technology.
See also: Is rain water safe to drink after boiling?
Methods of Estimating Average Rainfall
Estimating the average rainfall over a given period is essential in establishing the precipitation patterns of that particular area. Here are some of the methods used to determine the average rainfall.
Method 1: Arithmetic mean method
This is the simplest method of estimating average rainfall over a given area. It requires you to strategically place rain gauges over an area, summate all the recordings, and divide them by the number of rain gauges you used.
Method 2: The Thiessen Polygon Method
The Thiessen method requires you to join rain gauge stations using straight lines to come up with several triangles then divide the triangles from their edges to form polygons. Calculate the area occupied by each rain gauge to determine the size of influence for each.
Multiply each area by the amount of precipitation, then add them up and divide the total by the summation of the areas.
See also: How long can I store rainwater for plants
FAQs: How to Measure Rainfall at Home
What is the best way to measure rainfall?
The best way to measure rainfall is by using rain gauges. They are easier to use and interpret and will provide accurate information if used correctly. If you want to collect rainfall data over a large area, you can use radar, but their downside is that they are expensive and only used by professional meteorologists.
How do you measure rainfall in mm?
The calibration in most rain gauges is in mm or cm… The small units are mm units. Observe the measuring cylinder and record the water level on the lower meniscus. Also, note that 10 mm will give you a cm of rainfall.
How is Rainfall Measured for kids?
Kids need to learn how to measure rainfall. The easiest way for them to learn is by use of the rain gauge. Kids can also learn how to design and create DIY rain gauges for their own use at home. Use cm unit calibrations for them to have an easy time understanding.
Learning how to measure rainfall at home is the first step to establishing a healthy and beautiful garden or yard. The most common method of rain fall measurement is the manual use of simple rain gauges.
They are cheap and straightforward to use; all you need is to pick a suitable location to mount the rain gauge and collect the precipitation data every day to establish a trend.
References and Citations
University Corporation for Atmospheric Research [UCAR]: Measuring rainfall – it’s easy and difficult at the same time
North Dakota State University [NDSU]: Measuring Rain at Home
