The main objective of this study is to investigate temperature trend and distribution over 29 years period (1985 to 2013) in Makkah, Saudi Arabia, the holiest city for all Muslims. Monthly mean, maximum, and minimum temperature levels and their trends are investigated using Regression analysis and Theil-Sen nonparametric test. Also, trends in deviations from the reference period (1985-2013) are analyzed. The results showed that the number of hot days and nights increased annually by 1.5966 and 1.832, respectively, while the number of cold nights decreased annually by 0.4054 nights. Both Regression analysis and Theil-Sen test demonstrated positive trends in mean, minimum and maximum temperature levels. Trends are determined for various seasons and months of the year. The annual mean of daily mean, maximum and minimum temperature increased by 0.0398^°C, 0.0552^°C, 0.0398^°C per year, respectively. The minimum value of monthly mean temperature (Tmmean = 23.98^°C) was found in January, whereas the maximum value of the mean temperature (Tmmean= 35.95^°C) was found in July. Maximum value of monthly mean of daily maximum temperature (Tmmax = 43.88^°C) was found in June and minimum (30.54^°C) in January. The monthly mean of the daily minimum temperature (Tmmin) varied between a minimum of 18.82^°C in January and a maximum of 29.59^°C in August. From the above analysis it can be concluded that Makkah is suffering from a considerable warming temperature trend which is confirmed by the Theil-Sen non-parametric test and there is potentially an increasing medical risk from heat waves that will be more intense. This requires specific attention toward: the energy demands for extra cooling, water resources, draughts, and medical preparedness by the decision makers in order to minimize these risks to residents, pilgrims who gather annually to perform hajj rituals and other visitors.