Huge missed opportunity in this tool to actually answer the "wtf degrees?" question.
Fahrenheit temperature degrees are based on concepts of angular degrees (just as Centigrade is based on concepts of slope).
Many people know the Fahrenheit temperature scale is based in part on the coldest fixed temperature readily available to a scientist in the 1700's, namely the coldest temperature achievable when water ice is placed in a salt water bath (which he called 0 degrees).
Because choosing this fixed point meant Fahrenheit was basing his temperature scale on water, he viewed the coldest pure water temperature (ice) and the hottest pure water temperature (boiling) as significant in that they were, in his mind, opposite "directions" for water.
In his mind, frozen water and boiling water were therefore 180 degrees apart from each other.
Why did water ice and boiling water get these crazy 32 degree and 212 degree temperatures? The Fahrenheit scale is based on two constraints, not one.
The first, as is commonly known, is optimally salted ice water should be zero degrees.
The second constraint is that frozen water and boiling water should be 180 degrees apart.
212 degrees - 32 degrees = 180 degrees. If you constrain the temperature of salted ice to 0 and constrain the temperatures of frozen and boiling water to differ by 180, you get the fixed points of 32 and 212.
When Celsius invented the temperature scale we call centigrade, he used very similar constraints and also used angular thinking.
Both scales consider the freezing and boiling points of pure water to be significant.
The Celsius scale uses the freezing point of water as its zero, the Fahrenheit scale does not.
The Fahrenheit scale uses 180 degree based angular thinking to describe the transition from ice to steam, hence T(boiling) - T(ice) = 180.
The Celsius scale uses surveyor's percentage slope terminology (where a "grade", as in centigrade, of 100 corresponds to rise = 100% of run, or 45 degrees in angular terms), so T(boiling) - T(ice) = 100.
This page would be a wonderful vehicle for showing these connections (and the ice equals about 30 degrees and human body temperature equals about 90 degrees coincidences that Fahrenheit the numerologist found so compelling).
I hope the creator tweaks their page to show the actual angular history and relevance of these temperature scales. There is quite a bit of history of science in these relationships, all with the advantage of being readily accessible to a bright grammar school kid, which is a great age to stoke the fires of interest in science.