As the field of semiconductor nanolasers becomes mature in terms of both the miniaturization to the true sub-wavelength scale, and the realization of room temperature devices, the integrated treatment of multiple design aspects beyond pure electromagnetic consideration becomes necessary to further advance the field. In this review, we focus on one such design aspect: temperature effects in nanolasers. We summarize recent efforts in understanding the interplay of various temperature-dependent parameters, and study their effects on optical mode and emission characteristics. Building on this knowledge, nanolasers with improved thermal performance can be designed, and their performance evaluated. Although this review focuses on metal-clad semiconductor lasers because of their suitability for dense chip-scale integration, these thermal considerations also apply to the broader field of nanolasers.