What does the term "HZ" denote in a METAR report?

In a METAR report, "HZ" specifically refers to haze. This term is used to indicate the presence of dust, smoke, or any other particles that can reduce visibility in the atmosphere. Haze is characterized by a scattering of light, which can lead to a decrease in visual range, particularly over long distances. It does not imply fog, which has a greater density and results in significantly reduced visibility.

Understanding the significance of "HZ" is essential for interpreting weather conditions, especially for pilots and meteorologists who need to be aware of potential visibility issues while flying or conducting weather analyses. Recognizing this term helps users of METAR reports gauge the atmospheric clarity and take necessary precautions if haze is present.