Few things will earn you a nastier, contemptuous snarl from a Very Serious Scientist than using that lowly, scum-based Fahrenheit scale for measuring air temperature. "Celsius is the proper form of measurement," they haughtily trumpet, "because everyone else uses it." Everyone else is wrong.
The vast majority of us use the air temperature as a way to determine comfort when we go outside. Aside from weather forecasting, we don't really use the air temperature for much else. Even when we do—the swimming pool closes when the temperature drops below a certain point, for instance—it still relates to how we perceive temperatures. Like it or not, humans are sensitive creatures; a small shift in the temperature can mean the difference between ultimate comfort, sweaty misery, or a frozen shiverfest.
The two temperatures that matter most in practical uses are the freezing point and the boiling point. Thankfully, we don't worry about the boiling point unless it's pasta night, so we really only ever have to deal with one temperature for anything not related to comfort or safety: 32°F. When water freezes, it has wide-ranging implications from plant survival to building maintenance to the simple ability to walk to the mailbox without slipping and busting your butt on the driveway.
Celsius is a scale, as Very Serious Scientists enjoy pointing out, that revolves around the freezing and boiling points of water. It's nice and even: 0°C is freezing and 100°C is boiling. "It just makes sense!" Sure! Since Celsius is based on water, it would make wonderful sense to use Celsius for the environmental temperature if we lived in water. Until we sprout gills and start flapping around the Gulf, we should use Fahrenheit for air temperatures.
There's an old, bad joke about the two scales that goes around Twitter every once and a while: with Fahrenheit, you're really cold at 0°F and really hot at 100°F; with Celsius, you're cold at 0°C and dead at 100°C. Outside of the polar regions and deserts, the typical range of temperatures stretches from -20°F to 110°F—or a 130-degree range—with daily readings clustered even tighter for most of us. On the Celsius scale, that would convert to -28.8°C to 43.3°C, or a 72.1-degree range of temperatures.
Fahrenheit gives you almost double—1.8x—the precision* of Celsius without having to delve into decimals, allowing you to better relate to the air temperature. Again, we're sensitive to small shifts in temperature, so Fahrenheit allows us to discern between two readings more easily than Saint Celsius ever could.
Scientists need to use a standardized scale so they can easily share and use data from around the world without having to waste time (or make an error) trying to convert variables back and forth. As with other hard scientists, meteorologists use Celsius for weather forecasting, but even the most hardcore Celsius advocates in meteorology still begrudgingly produce public forecasts in Fahrenheit and miles per hour.
The metric system does make sense for certain aspects of daily life. Measuring rain and snow in millimeters or centimeters is easier (and allows for more precision*) than figuring out inches and feet. Measuring distance makes more sense in meters (1000 meters = 1 kilometer) than feet (5,280 feet = 1 mile). Air pressure is better in millibars or hectopascals (mb or hPa) than inches of mercury (inHg).
However, just because some aspects of the metric system make sense doesn't mean we should use it for everything, and therein lies the problem: the Very Serious Scientists get even angrier when you pick and choose. Boo! Variety is the spice of life. I like my distance in meters, my wind in knots, my weight in pounds , and my temperatures in Fahrenheit. If we were doing a science project (or running complex weather models), I would understand using a standardized system, but we're talking about day-to-day life here where communication and an ability to relate is key.
Fahrenheit makes more sense for precision* and as a way of communicating air temperature in a way that relates to how humans perceive temperatures. The main argument for Celsius is that the United States is one of only three countries (the other two being Burma and Liberia) that use Fahrenheit instead of Celsius. When an argument comes down to precision* and communication versus the good ol' bandwagon, the former should always (but rarely ever does) win.