John Dalton was probably born on 6 September 1766 in Eaglesfield, Cumberland. The date is widely accepted, although his birth was not entered in the Quaker register and some uncertainty remains.

Dalton was born into a Quaker family. His father was a weaver, and Dalton received relatively little formal education. He began teaching at a young age and moved to Kendal in 1781 to work at a school run by his brother.

His early scientific interests included weather and the atmosphere. Dalton began keeping regular meteorological records in 1787 and continued for the rest of his life. His study of gases led to work on the pressures exerted by individual gases in a mixture.

Dalton was also colour blind. In 1794 he presented research on the condition to the Manchester Literary and Philosophical Society. Colour blindness was later sometimes called Daltonism.

His best-known work concerned atomic theory. In the early nineteenth century, Dalton argued that chemical elements consisted of characteristic atoms and used relative atomic weights to explain how elements combined. His system contained errors, but it gave chemists a practical way to connect atoms with measurable chemical reactions.

Dalton spent most of his scientific career in Manchester. He was elected a Fellow of the Royal Society in 1822 and received its Royal Medal in 1826.