Does room temperature and humidity have any effect on burnout of the mold?
Absolutely. This is very critical because inappropriate conditions might not cure the mold properly so that additional time to cure the flask might be required and even that might not be sufficient. Generally speaking, the molds the room temperature should be higher and higher as the relative humidity rises. At ideal humidity of about 30 to 40%, room temperature around 23 degree C would be sufficient. On the other hand, at humidities in excess of 70% the room curing temperature ought to be above 30 degrees C (about 86 degrees F). Another difficulty arises when the molds are left curing overnight and the night temperatures drop while the humidity remains high. This is surely not good for the best curing of the investment.
