I'm electrospinning 10%wt PLA in Chloroform:DMF at a ratio of 2:1. The solution dries up and clogs the tip after about 5-10mins. Could this be due to the low outside temperature and humidity during winter increasing the solution's viscosity?
Changes in humidity will effect your Taylor cone and can lead to clogging of the tip. I wouldn't consider the viscosity change as the causing issue. Please have a look at some older posts, there you will find some suggestions to fix this challenge.
Check polymer-solvent especially Chloroform evaporation rate at room temperature. It is possible that its proportion causes the polymer to dry up soon at the tip of the needle.
you can increase the ratio of DMF to make the process more electrospinnability. Regarding increasing the humidity, you can increase it by using humidifier.