The first attempts at producing an outdoor thermometer were quite crude. Early cave paintings show a device (a stick) measuring about eight inches long (about 0.0002032 kilometers) with a small spherical container attached to one end. The most highly regarded theory is that early man would fill the container with water, throw it out of the cave and then try to convince a domesticated dog (or possibly a wild wolf) to go fetch the device. Most attempts probably resulted in the dog's refusal or eating of the human family by the wolf but a rare success would indicate whether or not the outside temperature was low enough to freeze water in a few seconds, which of course would suggest that it's not a beach day.
Researchers in the Middle Ages produced an improved device which they called the "One Shot Outdoor Thermometer." It was well known by that time that temperature varied significantly at different altitudes. Documentation of the device was not very good and so scientists can only guess how it worked but what we do know is that users would toss the thermometer high into the air and stand by as it crashed back to earth, then sniff at the resulting debris thus getting an indication of both the ground temperature and a fairly accurate prediction of impending precipitation.
In the early 1700s, German physicist Daniel Fahrenheit invented the mercury-in-glass outdoor thermometer. This thermometer was a long glass tube with temperature markings made over the entire length of the tube. A column of liquid mercury would expand and contract, indicating the outside temperature. The early marketing campaign of the device suffered a serious blow, however, when a large percentage of customers failed to read the enclosed operating instructions (most people back then couldn't read) and attempted to determine the outside temperature in a manner consistent with their experience with the One Shot Outdoor Thermometer. Thankfully for Fahrenheit's fledgling start-up company the legal industry was not nearly as efficient as it is today in its magazine advertizing of class action law suits and so most of the unhappy customers did not participate in the complaint alleging permanent brain damage suffered due to exposure to mercury (also likely key to the lack of plaintiff participation was the fact that most people back then couldn't read).
Around the same time that Fahrenheit invented the mercury-in-glass outdoor thermometer, someone came up with the idea for the alcohol thermometer. The initial idea was that should a customer mistakenly use it like a One Shot, at least there'd be something for him to drink (lap up) after the fact that wouldn't cause more brain damage than a typical evening at a tavern. The alcohol outdoor thermometer is similar to outdoor thermometers used in present time except that today an alcohol-kerosene mixture is typically used. The kerosene was added to cause customers to refrain from drinking the thermometer's entire contents if it is broken (most people in present time don't read directions).
DISCLAIMER: Very few (almost none) of the facts presented in the story are true. These "facts" are presented solely for the reader's amusement.