The United States uses the Fahrenheit scale for everyday temperature measurements mainly due to historical reasons. The Fahrenheit scale was developed by the German physicist Daniel Gabriel Fahrenheit in 1724 and was widely adopted in the British Empire before the metric system became popular. When the U.S. was founded, it inherited the Fahrenheit scale from its British roots.

Here are some key points that contributed to the continued use of Fahrenheit in the U.S.:

1. Historical Continuity: By the time the Metric System, including the Celsius scale, began to be internationally promoted in the late 18th century, the Fahrenheit scale had already been in use in America for many years. Changing an established system of measurement requires significant societal and infrastructural changes, which the U.S. largely did not undertake like most other countries did with the adoption of the International System of Units (SI).
2. Cultural Familiarity: Americans grew up using Fahrenheit, making it the norm and the more comfortable system for them. It is deeply ingrained in daily life, weather forecasts, recipes, and so forth.
3. Resistance to Metrication: While the U.S. has officially recognized the metric system since the Metric Conversion Act of 1975, efforts to fully transition to metric units have met with varying degrees of success. Temperature measurement remains one area where the Fahrenheit scale continues to dominate.

Despite this, Celsius is commonly used in scientific contexts in the United States and is taught alongside Fahrenheit in schools. Additionally, younger generations tend to be more familiar with Celsius due to its universal use globally and its prominence in educational materials. However, for practical and cultural reasons, Fahrenheit remains the default for everyday temperature readings in the U.S.