Display size. Watch out for the display size of a unit as a small display will make it difficult to read or understand what the thermometer says. As much as possible, get the largest display that your space can accommodate not just to get a much clearer reading, but also so you get a decorative element that makes a lot of impact in your outdoor space.
Backlight. This is a feature that you’d if you want a thermometer that can be easily read regardless of the lighting condition. Even if it’s nighttime and you did not switch on your patio lights, you would still be able to get a temperature reading and see it clearly because of the backlight. You also won’t have to be concerned about glare and sunlight during the day.
Quality. It's also important that you make sure your thermometer is one that’s made to last. Anything that’s placed outdoors will be exposed to harsh weather conditions. So, get the device that’s enclosed using a weather-proof or waterproof housing. Although water is your number one concern, you’d also have to ensure that your thermometer doesn’t get blown away by heavy winds.