The numbers on a Fahrenheit thermometer look random. Water freezes at 32 and boils at 212. Each one was picked for a reason, just not the reasons people expect.
The scale takes its name from Daniel Gabriel Fahrenheit. Britannica says he was born in Gdańsk, then Danzig, in 1686 and died in The Hague in 1736. He spent most of his life in the Netherlands as a physicist and maker of scientific instruments. Britannica credits him with an alcohol thermometer in 1709 and the mercury thermometer in 1714. Etymonline records the scale's name in English by 1753.
Sources disagree about when he set out the scale. Etymonline says he proposed it in 1714. Britannica and Wikipedia both give 1724.
Wikipedia describes three fixed points. Zero was a freezing brine of ice, water and ammonium chloride, a kind of salt. Ice in plain water was 32. Human body temperature was about 96. Etymonline instead says the zero was the lowest winter temperature he observed in Danzig in 1709. Wikipedia marks a similar German claim as failing verification, so the salt mixture is the better-supported account.
The odd numbers came from an earlier scale. Wikipedia says he built on the scale of Ole Rømer, which put freezing water at 7.5 and body heat at 22.5. Multiplying by four cleared the fractions, giving 30 and 90, as Britannica also records. He then moved them to 32 and 96, leaving 64 degrees between. Halving a space six times gives 64, so the marks were easy to draw.
Boiling water was not one of his anchors. He later observed it at about 212. Then the scale was rebuilt. In 1776 and 1777 a Royal Society committee led by Henry Cavendish fixed freezing at exactly 32 and boiling at exactly 212. Body temperature, no longer a reference point, came out at about 98.6.
Etymonline adds one more twist. It describes Fahrenheit as an abstract surname meaning, literally, "experience." For a scale built by trial and adjustment, the name fits.