The accuracy of a weather station is the degree to which it measures temperature and other meteorological variables. The precision of a weather station is how well its measurements are repeatable or consistent from one reading to another. Both terms can be used interchangeably in most cases; however, there are some essential differences between them that you should know about before using either time.
In general, an accurate measurement means that your instrument has measured what it was supposed to measure. For example, if you have a thermometer with a mercury-filled bulb inside, then when you take a reading on the outside surface of the glass tube, you will get a more precise reading than if you were to read directly into the bulb itself.
This is because the outer surface of the glass tube is not affected by air currents around the bulb as much as the inner surface would be. In addition, the outer surface does not heat up as quickly as the bulb’s interior, so readings taken at this location may give slightly different results over time.
An excellent way to think about precision is to imagine taking several identical copies of something and measuring each composition against a standard object. If all these copies are very close together, they will probably agree quite closely with one another. However, if you put two copies of the same thing far apart across town, their measurements might differ significantly.
A similar concept applies to instruments such as thermometers. When you use a thermometer indoors, for instance, you want to make sure that the thermometer’s internal sensor is exposed to the same conditions as those found outdoors. Otherwise, the indoor reading could vary significantly from outdoor temperatures.
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Accuracy vs. Precision
There’s another important distinction here: Accuracy refers to the ability of the instrument to identify something correctly, whereas precision refers to the ability to reproduce the results obtained using the instrument repeatedly.
So, for example, if you take 10 samples of the same thing and get 9 correct answers and 1 incorrect one, you’d say that the instrument was 95% accurate. On the other hand, if you retook those same 10 samples but got all 10 right, you’d say that it had 99.9% precision.
In practice, however, instruments don’t usually work like this. Instead, they tend to fall somewhere along a continuum where the closer you get to perfect accuracy, the less precise the instrument becomes. That’s because many devices rely on analog signals whose output varies continuously rather than discretely. As such, their performance tends towards the lower end of the spectrum.
On the other extreme, some instruments provide extremely high levels of precision. One typical example is a laser interferometer, which relies on interference patterns created by light bouncing off mirrors attached to moving objects. The resulting pattern can then be analyzed to measure distances or angles down to an angstrom fraction accurately.
However, since lasers operate according to quantum mechanics, they’re inherently nonlinear, meaning that slight input variations cause significant output fluctuations. For this reason, most commercial systems use multiple beams operating simultaneously, allowing some degree of error cancellation.
How to choose?
Many different weather stations are available today, ranging from inexpensive models to those costing thousands of dollars. The best way to choose one is to research online or talk to friends who have them installed. You want something that provides reliable readings over long periods without worrying about battery life. If you’re looking into purchasing an outdoor unit, make sure it comes with a warranty, so if anything goes wrong, you’ll be covered.