Thermal comfort of outdoor spaces in Lahore, Pakistan: Lessons for bioclimatic urban design in the context of global climate change

• We measured the microclimate in two contrasting outdoor environments in Lahore, Pakistan.
• The air temperature and humidity did not vary between or across sites.
• Shade from the sun was determined to be the most effective way to reduce the heat loads on people.

Humans interact with urban microclimates through exchanges of energy. A surplus of energy can create thermal discomfort and be detrimental to human health. Many cities in warm regions all over the world are forecast to become very hot through global climate change. Some cities already experience extreme heat and have done so for centuries. We conducted a study of one such city in order to generate design guidelines for creating thermally comfortable outdoor places. In the hot, dry city of Lahore, Pakistan we compared the microclimates of two very different outdoor spaces. The first place was the 16th century Shalimar Garden, which contains much green infrastructure and water features. The other example was the hard-surfaced courtyard of the contemporary Alhamra Art Centre. In both places we measured the microclimatic characteristics and used those data to simulate thermal sensation through the energy-budget model COMFA. The measured air temperature and humidity in both spaces was similar. However, the solar radiation that would be received by a person in the Alhamra courtyard was much higher than in Shalimar Garden and was the main determinant of thermal discomfort. Results from this study can inform other cities in hot, dry climates about design responses that provide more outdoor thermal comfort and prevent health-threatening heat.