The temperature range for a capacitor is determined entirely by the type of dielectric that is used. Many capacitor make use of plastics materials, so that the temperature range must be such that the material is used well below its melting point. In addition, several types of plastics materials undergo serious changes in form at very low temperatures, becoming brittle and even cracking.
The temperature coefficients of capacitor can be negative (which is more common) or positive, and a few types can have very large temperature coefficients, although values of ±200 ppm/°C are usual. For some applications of capacitor, such as decoupling, temperature coefficients are almost irrelevant and tolerances are not particularly important either. The most critical applications are for capacitor which form part of a tuning circuit, where a large temperature coefficient could cause mistuning to occur as the temperature changed.
Modern oscillator circuits would normally use some form of automatic control, but careful selection of tuning capacitor is also necessary to prevent the tuning from falling out of the range of the automatic controls because of variations in capacitance of a fixed capacitor.