I'm wondering, whether there is a correlation between environmental factors like temperature and the ability to solve problems (say math exercises). Although I am sure this has been studied, maybe someone could point me to a reference.
As @what mentions Pilcher et al (2002) provide a meta-analysis of the effect of hot and cold temperature on performance. They found that cold temperatures of 10 degrees celsius resulted in an average reduction in performance of 14.88% and that hot temperatures of 32 degrees celsius resulted in a decrement of 13.91% relative to more neutral temperature conditions.
The study does discuss how type of task and duration of task moderate the effect of temperature on performance. However, as is often the case with meta-analysis, I found the results to be somewhat confusing and not readily explainable by a coherent theoretical model.