This paper determines the impact of ambient temperature on energy consumption of a variety of vehicles in the laboratory. Several conventional vehicles, several hybrid electric vehicles, a plug-in hybrid electric vehicle and a battery electric vehicle were tested for fuel and energy consumption under test cell conditions of 20°F, 72°F and 95°F with 850 W/m₂ of emulated radiant solar energy on the UDDS, HWFET and US06 drive cycles.At 20°F, the energy consumption increase compared to 72°F ranges from 2% to 100%. The largest increases in energy consumption occur during a cold start, when the powertrain losses are highest, but once the powertrains reach their operating temperatures, the energy consumption increases are decreased. At 95°F, the energy consumption increase ranges from 2% to 70%, and these increases are due to the extra energy required to run the air-conditioning system to maintain 72°F cabin temperatures. These increases in energy consumption depend on the air-conditioning system type, powertrain architecture, powertrain capabilities and drive patterns. The more efficient the powertrain, the larger the impact of climate control (heating or cooling) on the energy consumption.A wealth of vehicle test data and analysis is used to explain the nuances of the behaviors of the different powertrain architectures at the different temperatures. Additionally, test procedure details, charge-sustaining challenges, cold-start penalties, cabin temperature pull-up and pull-down, idle fuel flow rates, engine operations, impact of degree of hybridization, and battery system resistances are discussed. The Appendix provides time history graphs of all the data.