Abstract

This study analyzed maximum and minimum temperature data over forty-one years from thirty locations in Egypt to determine variations in the country’s diurnal temperature range (DTR). Egypt is experiencing a general trend of rising maximum and minimum temperatures across all regions. Minimum temperature trends exceeding maximum trends suggest nighttime warming. The DTR analysis highlights a predominant negative trend at most stations, suggesting a narrowing gap between daily maximum and minimum temperatures. Results showed that DTR is higher in central and southern Egypt compared to the northern Delta region. The observed negative trend at twenty-five stations, contrasted by only one station exhibiting a positive trend, indicates a widespread and significant pattern. This negative trend, averaging a decline of −0.08°C per decade, is particularly pronounced in the central and northern regions, extending to eastern and southern areas. The seasonal analysis of DTR reveals distinct patterns, with a negative trend in all seasons except autumn, where a positive trend emerges. This indicates that the gap between daily maximum and minimum temperatures is narrowing for most of the year, except during autumn. Simultaneously, the positive trends in maximum and minimum temperatures across all seasons suggest a general warming pattern. All six regions show a decreasing trend of DTR and no significant differences in DTR. The highest averages were observed in the Red Sea region, which has the most rapid DTR decreasing rate, while the Nile Delta and Middle Egypt have the slowest DTR decreasing rate, at 0.11°C per decade.