Last year was by far the hottest year on record in the United States. Here's 2012's heat by the numbers:

- Average annual temperature: 55.32 degrees F, a record. The old record was 54.32 degrees, set in 1998.

- Weather stations across the Lower 48 states setting all-time high temperatures: 356.

- Weather stations setting all-time low temperatures: Four.

- Number of states that had their warmest year: 19.

- Months in 2012 that set U.S. heat records: March and July.

- Number of people who experienced at least 10 days of 100-degree heat: 99.1 million.

- Number of consecutive months that the United States had warmer than average temperatures: 16.

- New all-time warmest temperature in South Carolina: 113 degrees.

Source: National Climatic Data Center.