Natural hydraulic lime (NHL) is considered to be more environmentally friendly than Portland cement (PC) since it has a lower calcination temperature and the ability of carbon dioxide (CO
2) sequestration during the hardening process. Both factors contribute to the fact that NHL has higher environmental credentials. Both of these characteristics contribute to the production of the NHL. On the other hand, NHL is more susceptible to the effects of climate throughout the processes of setting and hardening, which is especially true in environments with high relative humidity. This study evaluated the influence of high temperature and humidity conditions on NHL mortars. Three settings were studied to examine mortar’s primary chemical and physical properties. According to the findings, mortars that were allowed to cure at higher temperatures achieved their initial strength more quickly. However, this strength gradually reduced over time, which put the mortar’s quality at risk. This finding also helps to show the challenges associated with using NHL materials in their current form in high-temperature and high-humidity settings, such as tropical regions.