WD-40 has a pour point of -81.4 degrees Fahrenheit. This means that the liquid is still fluid up until it reaches this temperature, and should still flow. Below that, it may gel or freeze, and become ineffective. However, some people have reported that WD-40 becomes less effective at temperatures of 5 degrees Fahrenheit and lower. For best results, keep it in a cool (not cold) place out of direct sunlight.