This paper details the results of an experimental study investigating the influence of daylight illuminance levels and indoor temperatures on objective and subjective performance evaluations, investigated through paper-based tasks and questionnaires, respectively. Experiments were conducted in an office-like test room with controllable indoor temperature and easy-to-change glazing visible transmittance. A total of 84 participants took part in the experiment, performed only under clear sky conditions to avoid variations in illuminance. In a randomized order, participants were exposed to three daylight illuminance levels (on average 140, 610 and 1440 lux) at one of three temperature conditions: 19, 23 and 27°C. Results show that objective performance outcomes were not affected by daylight illuminance or temperature, nor by their interactions, but only by the order of the test presentation ( indicating a learning effect). Of the subjective responses, only perceived concentration was affected by daylight conditions, with a self-reported lower concentration under the low illuminance level.