Designers must consider outside conditions during all seasons and their impact on the operation of the building and HVAC systems. This paper, co-written by IMEG’s Jeff Boldt, examines key design strategies for projects whether they are in climates that are humid or arid, hot or cold. Reprinted with permission from ASHRAE, this paper was originally published as the “Engineer’s Notebook” in the June 2021 issue of the ASHRAE Journal.