<![CDATA[Frost in the Dieng Highlands is a localized agrometeorological hazard that appears during selected tropical highland nights, yet its recurring near-surface meteorological structure remains insufficiently documented using high-temporal-resolution observations. This study characterizes the meteorological signature of Dieng frost events using quality-controlled 10-minute Automatic Weather Station (AWS) observations from 2021 to 2025. Observations were arranged into nocturnal windows from 19:00 to 06:50 Western Indonesian Time and classified into frost and non-frost nights using 50 documented event dates. Temporal distribution, median nocturnal composite profiles, Mann-Whitney U tests, Cliff's delta, and Spearman correlation were applied to temperature, humidity, dew-point depression, wind speed, rainfall signal, cooling rate, and pressure. Among 1,819 analyzed nights, 50 were classified as frost nights, corresponding to 2.75% of the observation period. The events were concentrated in the dry-season months, especially July, followed by August and June. Frost nights showed a persistent nocturnal thermal pathway, with median night-mean and minimum temperatures of 6.11 °C and 2.65 °C. They were also calmer, had stronger negative cooling rates, and lower rainfall signals, whereas dew-point depression and relative humidity did not differ significantly between classes. These results indicate that Dieng frost is best understood as a combined cold, calm, humid, radiatively efficient, and seasonally dry nocturnal signature rather than as a low-temperature condition alone.]]>
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