Identifikasi Zona Kenyamanan TermalL Wisatawan di Kawasan Pesisir Menggunakan K-Means Clustering Berbasis Heat Index (HI) DAN DISCOMFORT INDEX (DI) (Studi Kasus: Pantai Setrojenar)

Setrojenar Beach in Kebumen is a coastal tourism destination with relatively high
visitation, yet systematic information on tourists’ thermal comfort conditions
remains limited. This study aims to identify thermal comfort zones using K-Means
Clustering based on the Heat Index (HI) and Discomfort Index (DI), and to analyze
temporal patterns by hour and month to identify more favorable periods for
tourism activities. The study uses hourly meteorological data from NASA POWER
for the 2020–2024 period, consisting of air temperature and relative humidity, with
43,848 initial observations. After data selection and cleaning, 23,149 observations
were retained for analysis. The results indicate that two clusters provide the
optimal clustering solution, producing two thermal zones: a Comfortable Zone
with a mean HI of 26.50°C, representing 26.7% of the observations, and a High-
Alert Zone with a mean HI of 32.54°C, representing 73.3% of the observations.
Temporal analysis shows that 06:00 has the highest proportion of the Comfortable
Zone at 35.6%, while 12:00 has the highest proportion of the High-Alert Zone at
77.2%. August is identified as the most favorable month, whereas April exhibits
the most thermally stressful conditions. These findings indicate that thermal
conditions at Setrojenar Beach are predominantly characterized by conditions
requiring caution. Morning hours before 09:00 are identified as relatively more
favorable for tourism activities based on thermal comfort conditions.