Prepositions. They can serve as a compliment to an adjective or verb, yet with over three dozen of them in the English language (more in German and other languages), they can be a nuisance as the meaning and usage of them are sometimes confusing, especially when a person learning English as a foreign language wants to know the equivalent in the native tongue. Sometimes there are pairs of prepositions, which mean the same in general but are used for different purposes, such as over and above, through and via, ….
or this one: under and below.
While both prepositions mean anything below average, below the line or even below zero, one deals with moving down towards and beyond the threshold- which is under- while the other stays under the threshold- below.
For example, one can say “I went under water” or “I crawled under the bed”, for movement and “The sunken ship is 300 meters below sea level”, or “The neighbors living below us are noisy”, to describe something stationary and still. Yet, can we make the difference with the thermometer?
As a general rule, a temperature can be below zero or a certain degree because it implies that the mercury is constantly at this mark and cannot move at a fast pace. This is independent of the real air temperature which can be warmer or colder, pending on the humidity and the dew point. That means the temperature may be -1° Celsius (34° Fahrenheit), but can be warmer because of the high humidity and the sun, or colder because of the dry air, low humidity and the wind. Since the 1990s, the Real Feel Temperature Index has been using several factors to compare the temperature on the thermometer and how it feels on the person in reality, based on light, wind and moisture.
But can a temperature go under zero?
As a general rule, you cannot use under when you describe the temperature because the mercury is so slow that it would take many hours for it to fall. The same applies to over and above when describing the increase in temperature, which is why we use above only. However, as history presents itself, there are some exceptions to the rule.
If a student asks you (as a teacher) why we use below zero, instead of under zero, you can share him/her a pair of stories of how certain regions actually went under zero- in a very short time, during two very tragic events in the United States. Here they are in summary:
- November 11, 1911: According to weather historian Jim Lee, a very strong cold front carrying first strong thunderstorms with rain and tornadoes, and afterwards sleet, snow and blizzard conditions struck the Central Plains region, causing temperatures to plummet by double digits within an hour. This included Springfield, Missouri, where temperatures dropped by as much as 40° F in 15 minutes. From 80°F (27° C) before this drammatic drop at 3:45pm, to 40° F (4° C) fifteen minutes later, to its bottoming-out low of 13° F (-11° C) by midnight, the city was one of over two dozen, whose record high and low temperatures were recorded on the same day, which included Oklahoma City and Kansas City. Over a dozen tornadoes followed by blizzards in this Great Blue Norther, caused over $3 million in damages- the heaviest hit areas were in the Ohio River valley, as well as in Indiana, Wisconsin and Michigan. 13 people lost their lives with over 50 people injured.
- November 11, 1940: Known as the panhandle hook, this tragic event reshaped the way forecasts are given. On this day, hundreds of people took the day off from work to go hunting for ducks and pheasants with temperatures in the mid to upper 60s Fahrenheit (18-20° C), many of them were underdressed for the occasion. During the afternoon, the temperatures dropped dramatically to a point where by midnight, they were at or below 0°F (-20° C)!!! Many hunters were taken by surprised and tried to seek shelter from the cold, icy wind, combined with heavy snow and white-out conditions. Fifty degree drops were recorded in a region of over 1000 kilometers long, including states like Minnesota, Nebraska and Wisconsin, where 1-2 foot snowfall combined with 20 f00t (6 meter) drifts were recorded. Collegeville, Minnesota set a record for the most amount of snow in a storm with 27 inches (69 cm). 145 people perished in the snowfall, many of whom froze to death. 49 of the deaths were recorded in Minnesota, of which half of them froze to death. Rescue efforts by pilots Max Conrad and John Bean by locating stranded hunters and providing aid saved many lives. The storm resulted in changes in weather forecasting as 24-hour mandatory coverage and improved technology was later introduced, which is still in use today but with advanced technology.
These two events show that temperatures can go under zero if the mercury moves quicker than it should, even though in a grammatical sense, one should use below as it shows consistency on a longer termed basis. If your students ask why below is best used for temperatures below the mark instead of under, it is best to say that under is used for movement purposes but in quicker form and also on a temporary basis. It is unknown how (long) a mole can live and dig under the ground, but treasure and cellars can be found below the ground (level) because they are permanent. Yet when it comes to temperatures, especially after reading the examples of the storms that occurred on Veterans Day in the States, some exceptions do apply, although they very rarely happen. So use below zero instead of under zero unless you want to be that brave duck hunter wishing to hunt while in the snow. 😉