What Was the Hottest Day in the US
The hottest day in the US, according to NOAA and the National Centers for Environmental Information, was July 10, 1913, when Furnace Creek Ranch in Death Valley, California, reached 134 degrees Fahrenheit (56.7 degrees Celsius). This remains the highest reliably recorded air temperature in the United States and one of the highest on Earth, with modern data from NOAA confirming it as the benchmark for US heat records.
NOAA and the World Meteorological Organization continue to use the 1913 Death Valley reading as the official US record, while noting that measurements from other locations, such as Greenland Ranch in Death Valley, have been reviewed for accuracy. The National Weather Service and NOAA climate data portals provide the latest updates on extreme heat events and historical comparisons.
Where and When the Hottest US Day Occurred
The record was set at Furnace Creek Ranch in Death Valley National Park, California, on July 10, 1913, during a prolonged heatwave that affected the Mojave Desert region. NOAA climate scientists cite this event as a critical data point in long-term temperature records, and the National Park Service maintains historical weather logs for the area.
Death Valley regularly experiences extreme heat, with multiple locations in the region approaching or exceeding 120 degrees Fahrenheit in recent years. NOAA's National Centers for Environmental Information publishes annual state climate summaries and extreme event reports that track how often new daily or monthly records are tied or approached.
How US Heat Records Are Verified and Compared
NOAA's National Centers for Environmental Information validates historical temperature records using station metadata, instrumentation standards, and peer-reviewed methods. The agency maintains the Global Historical Climatology Network, which includes Death Valley data, and publishes technical reports explaining how extreme values are assessed for accuracy and consistency.
Climate researchers use NOAA data to compare the 1913 Death Valley record with modern heatwaves, noting that while daily records may be tied, the all-time US high remains 134 degrees Fahrenheit. The EPA's climate indicators and NOAA's climate.gov site provide accessible summaries of extreme heat trends, data quality, and the role of urban heat islands and station siting in temperature observations.