It was introduced in 1992 & the record 43.3 was set in the high Andes, where stratospheric ozone levels are naturally low

On Tuesday, October 7, 2025, Jeopardy! featured a challenging Final Jeopardy clue in the category Science Records. The clue was: “It was introduced in 1992 & the record 43.3 was set in the high Andes, where stratospheric ozone levels are naturally low.”

What is the UV Index?

This clue pointed to a scientific tool used to measure ultraviolet radiation levels and referenced the conditions that can cause it to reach extreme values. The correct answer highlighted the intersection of environmental science, atmospheric chemistry, and public health.

Understanding the UV Index

The UV Index (UVI) is a globally standardized measurement system introduced in 1992 by the World Health Organization and other international agencies. It quantifies the strength of sunburn-producing ultraviolet (UV) radiation at a particular place and time. The scale typically ranges from 0 (minimal risk) to 11+ (extreme risk), but under rare and extreme circumstances, values can exceed that range.

The UVI serves as a public health tool, designed to warn people about the potential dangers of overexposure to UV radiation. Prolonged exposure to UV rays without protection can lead to sunburn, skin aging, eye damage, and increased risk of skin cancer. The higher the index, the greater the risk and the faster sunburn can occur. Values above 11 are exceedingly rare and are almost always recorded at high elevations, near the equator, or in areas where atmospheric conditions allow more UV radiation to reach the surface.

The Record-Breaking UV Index

The value referenced in the clue—43.3—was documented in the Andes Mountains of South America, specifically near Bolivia. This measurement, recorded by researchers in 2003 and published later, remains the highest ever recorded. It occurred at an altitude of over 12,000 feet, where thinner atmosphere provides less shielding from harmful rays.

The extraordinarily high UVI reading was influenced by a combination of factors: high elevation, a thin ozone layer, clear skies, and ground-level reflectivity from light surfaces like snow. The ozone layer plays a crucial role in filtering out much of the sun’s harmful UV-B radiation. In the Andes, natural dips in ozone concentration—combined with human-caused ozone depletion—can lead to extremely elevated UV exposure.

Why the Andes Experience Extreme UV Levels

The Andes region is one of the few places on Earth where such high UV readings are even possible. The mountains lie close to the equator, where the sun’s rays strike the Earth most directly year-round. In addition, the stratospheric ozone layer over the Andes can be thinner than in other regions, especially during the Southern Hemisphere’s summer months.

Other contributing factors include the area’s elevation, which places observers closer to the sun and above more of the Earth’s UV-filtering atmosphere. Snow-covered surfaces also reflect UV radiation, significantly intensifying the exposure. These conditions together make high-altitude Andean regions a hotspot for UV radiation studies.

Broader Implications for Climate and Health

The UV Index is more than just a weather stat; it’s a crucial public health advisory tool. Health authorities around the world use UVI forecasts to recommend protective measures, such as wearing sunscreen, sunglasses, and long clothing, or avoiding sun exposure during peak hours. High UVI readings like those in the Andes, while extreme, underscore how variable and potentially dangerous UV radiation can be.

Increased UV exposure is also a marker of ongoing environmental concerns. Although global efforts like the Montreal Protocol have helped reduce emissions of ozone-depleting substances, the ozone layer is still in recovery. Regions like the Andes serve as natural laboratories for understanding how solar radiation interacts with our changing atmosphere.

A Clue Rooted in Science and Geography

This Final Jeopardy clue elegantly connected scientific knowledge with a real-world extreme. Contestants had to recognize that the “record 43.3” referred not to temperature, pressure, or altitude—but to ultraviolet radiation. Understanding the link between atmospheric science, geography, and global health was essential to getting this one right.

It also served as a reminder of the importance of science communication. Tools like the UV Index are not only technical achievements—they’re part of how the public stays informed and safe in a changing world