This market resolves as YES if a verified air temperature reading of 60 Celsius (140 Fahrenheit) or higher is taken on Earth's surface at any point between market creation and December 31, 2039 (inclusive.) Otherwise, this market resolves as NO on January 1, 2040.

Additional context

The current record-holder is 56.7 Celsius/134.1 Fahrenheit, measured at Furnace Creek in Death Valley in 1913. Some scientists argue that the temperature was measured incorrectly and should be decertified as the record holder; if so, the highest temperature would either be 54.4 Celsius at Furnace Creek (if certified; measured in 2020 and 2021) or 54.0 Celsius in Death Valley (2013) and Kuwait (2016.)

Climate models suggest that Earth's climate will continue to warm over the next several decades, making extremely high air temperatures more likely - particularly as heatwaves become more common and more intense.

Fine print

The reading must display a temperature equal to or greater than 60.0 Celsius for this market to resolve as YES. An air temperature reading of 59.5 C, 59.51 C, or 59.99 C would not be sufficient for a YES resolution.

The temperature must be verified by the World Meteorological Organization (WMO.) If an air temperature of 60 C or higher is measured by 2040, but hasn't been verified by 2040, then this question will remain open until the measurement is either verified or debunked. This may take a few years. The initial closing date is January 1, 2040, but it will be pushed back if needed. Only an air temperature measured by a reputable organization like the National Weather Service is sufficient to cause this question to remain open - a photo of a thermometer in someone's backyard is too easy to fake.

Only air temperatures measured on Earth's surface are sufficient to cause this market to resolve as YES. Sattelite readings of air temperatures are not as reliable. Ground temperatures obviously don't count - the record ground temperature is already over 90 Celsius. The reading can be anywhere on the Earth's surface, in any country, at any time of day. The air temperature must be measured outside of a building, and measured in a way that is standard for the measurement of weather/climate data.

If the World Meteorological Organization no longer exists by the time a record is set, I'll resolve this based on verification by another trustworthy meteorological body such as NOAA, the National Weather Service, etc.