Have you seen a rain spell pass over your garden, only to find your rain gauge collected less water than you expected? Or maybe your readings have been looking a little inconsistent, leaving you wondering whether your weather instrument is working as it should.

A rain gauge is a useful tool for understanding weather patterns in your own garden or outdoor space. Keeping track of rainfall and can help you make more informed decisions about your garden and plants overall health. With a little care and a consistent routine, you can get more from your rainfall measurements.

Before assuming your rain gauge could be broken, here are some common things to check if your rain gauge does not seem to be measuring rainfall as expected.

Is your rain gauge in the right position?

Where you place your rain gauge can make a real difference to how much rainfall it collects, so finding the right spot in your garden is a great place to start when checking the accuracy of your readings.

Walls, fences, trees and buildings can affect the way rain reaches your gauge. For example, an overhanging branch may intercept rainfall before it reaches the funnel opening, while nearby structures can alter the airflow around the instrument.

Rain doesn’t always fall vertically. When wind blows, it can change the direction of falling rain, and the airflow around tall buildings and trees can affect how much water enters your rain gauge. Therefore, when deciding where to place your instrument, aim for a position with clear exposure to rainfall and minimal interference from nearby obstacles, while following the installation guidance included with your instrument.

Take a look around your garden. Is your rain gauge positioned beneath a tree, close to a fence or beside a wall? If so, try to place it at least twice the height of any surrounding objects away from them. For example, a 10ft tree should ideally be around 20ft away. Aim to position your rain gauge around 45cm above the ground, too. This helps reduce the effects of wind while keeping it high enough to prevent raindrops from splashing up from the ground and into the funnel.

If you have a digital rain gauge, check that your outdoor sensor is securely mounted in an area with minimal obstruction. Our CM7015 Wireless Rain Gauge can be mounted on a pole or a wall or even a specially designed mounting shelf to ensure the most accurate results.  If you are concerned that the position of your rain gauge is affecting your results, try moving to a more open and sturdy location.

For more guidance on how to set up your rain gauge, visit our blog: How to Measure Rainfall: A step-by-step guide | ClimeMET

Is your rain gauge level and securely mounted?

Once you’ve checked your gauge’s location, take a closer look at how your rain gauge is mounted. Is your rain gauge tilted out of position, where it may not be collecting rainfall as it should? Is your rain gauge mounted at the bottom or even halfway up your garden fence?

For the most accurate readings, your rain gauge should be sitting level, whether it’s placed on a table, a flowerbed or mounted on your garden fence. Strong winds, soft ground and accidental knocks during days spent in the garden can cause your gauge to shift out of position, so it’s important to check that it’s secure and doesn’t wobble or lean to one side. Taking a moment to check your gauge after a particularly windy spell or a busy day in the garden can help you spot any changes before they affect future readings.

If your rain gauge is mounted on a fence, check that the funnel sits above the top of the fence panel rather than below it. This helps prevent the fence from obstructing rainfall and allows rain to collect in your gauge more freely.

If you have a digital rain gauge, check the built-in level, to make sure the sensor is positioned correctly. Our CM7015 rain gauge has a built-in bubble level to help with easy installation. Keeping the sensor level and secure is important because it allows the tipping mechanism to sit properly and tip from side to side. If your rain gauge isn’t mounted correctly, it can lead to over- or under-recording rainfall measurements.

Could a blockage or buildup be affecting your readings?

Rain gauges live outdoors, so it’s not surprising that they can collect more than just rainwater…

Leaves, twigs, insects and other garden debris can collect in your rain gauge over time. This can interfere with your gauge's ability to collect rainfall. If water can’t move through the funnel as it should, your readings could be skewed.

Check your funnel or opening for anything that could be restricting the natural flow of water. Even a small obstruction can affect how much rain your gauge collects. Carefully remove debris, and if needed, separate the funnel from the gauge, give both a quick rinse, then reset it in an open, level and obstruction-free position.

For digital rain gauges, check the collection cone and any filters for blockages. Our CM7015 Wireless Rain Gauge has removable side trays that can be wiped clean to help clear small blockages that develop over time. If your display shows no or very little rainfall despite wet weather, a blocked mechanism is a possible cause worth checking.

Regular checks are particularly worthwhile during autumn, when falling leaves and other debris can build up around your instrument.

Are you recording rainfall consistently?

Sometimes the problem may not be the rain gauge itself, but the way rainfall is being recorded. To compare readings over time, it’s important to follow a consistent routine and ensure you're taking measurements from the same viewpoint each time.

When checking your rain gauge, observe the measurement at eye level to avoid misreading the scale.

It’s also important to keep track of the measurement period. Choosing a specific time to check and record the measurements from your rain gauge makes it easier to compare totals and record changes over time.

Check your gauge after heavy rainfall, as some manual rain gauges have limited measuring capacity. If the water exceeds that capacity, it could overflow, and you would lose your overall rainfall total. Digital models may offer preset time periods and automatically reset measurements. For example, our CM7015 Wireless Rain Gauge lets you view rainfall measurements over one hour, 24 hours, a week or a month, as well as track total rainfall over a specific period.

To make recording your rainfall easier, try using a rainfall chart to keep all your measurements organised in one place, rather than relying on memory or random notes on your phone. Our Annual Rainfall Chart provides space to record daily readings, track monthly totals and averages, and look back on your rainfall measurements throughout the year.

Measure every drop:  

With a few simple checks and a little consistency, your rain gauge can become a helpful part of your garden routine, giving you a clearer picture of the rainfall your garden receives. If you'd like to take your observations a little further, why not explore our guide to starting your own rainfall study and discover more about what you can learn from keeping track of the rain?

FAQs:

• Can I use my rain gauge readings to help care for my garden?
• Yes, you can! Keeping track of rainfall can help you make more informed decisions about watering your garden. By monitoring how much rain your garden gets over several days and weeks, you can better understand whether your plants are in need of a little water, rather than relying on guesswork alone. However, rainfall readings are only one part of the picture, as soil type, moisture and individual plant needs can also influence how much watering is needed.
  
  

• Why does my rain gauge show a different rainfall reading than the local weather forecast?
• Rainfall can vary over short distances, so the amount collected in your garden may differ from the measurement reported by local weather stations. Showers can be localised so one area may receive considerably more than another. Differences in location, equipment and recording periods can all influence varied results. Your rain gauge, however, will provide you with a useful record of rain fallen in your own outdoor space.

• How often should I clean my rain gauge?
• Check over your rain gauge regularly and clean it whenever you notice leaves, dirt or other debris building up in or around your rain gauge. Frequency will depend on your surroundings, as gauges positioned near trees or hedges may collect debris quickly. Checking it more often during autumn and particularly windy weather is recommended. 

• Do you need to empty a digital rain gauge?
• Not usually. Many digital rain gauges are designed using a tipping mechanism that measures rainfall and then allows the water to drain out naturally. Rainfall readings can be seen on the connected display console.