Kilimanjaro’s daytime and nighttime temperatures follow different trends
Kilimanjaro’s temperature changes differ by elevation and time of day in a peer-reviewed observational study. Satellite and field measurements show daytime cooling at some middle elevations and nighttime warming across most lower zones. The trend maps describe clear skies during 2004–2019. Changes in vegetation accompany this contrast, alongside other influences on temperature across the mountain.
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Middle elevations cooled by day while lower zones warmed at night
Temperature trends on Tanzania’s Kilimanjaro do not follow one pattern throughout the day. In a single peer-reviewed observational study, the summit vicinity warmed weakly during daylight, while some middle elevations cooled. Lower zones mostly warmed after dark; the summit then changed little. Where vegetation increased, temperatures tended to fall during daytime and rise at night. Snow, reflectivity, fires, land cover and cloud distribution can also influence the pattern; vegetation was not the only possible influence.[1]
Surface heat and air temperature require separate measurements
Field observations from 2004–2024 span approximately 5,000 m of elevation. The research combines them with MODIS satellite measurements at four daily overpass times and approximately one-kilometre resolution. Satellites measure the land surface, whereas stations measure the air. A 10–15 °C difference can separate the warmer surface from the cooler air in the dry season. Separate daytime and nighttime models connect the measurements; their root-mean-square errors were 1.76 °C and 1.36 °C, respectively.[1]
The trend maps cover clear skies through 2019
Mapped trends use 2004–2019 rather than the entire observation period because later orbital changes altered satellite sampling times. Clear-sky sampling leaves cloudy periods outside the estimates. A station also represents less ground than a satellite pixel, while cloud-mask errors and measurement frequency can affect the results. The observed contrasts therefore concern the elevations, times and clear-sky conditions measured on Kilimanjaro. They do not establish one temperature trajectory for tropical mountains generally.[1]
