At what sub-zero temperature should car windshield washer fluid be replaced with antifreeze fluid?

[JaxsonRose]

Car windshield washer fluid should be replaced with winter-grade fluid when temperatures approach 0°C. Replacement of car windshield washer fluid: The specific replacement should be chosen based on the environmental temperature of the vehicle's usage area. If winter temperatures are extremely cold, antifreeze washer fluid must be used. Options include -25°C, -30°C, and -40°C rated fluids. In China, -30°C fluid is generally sufficient, but for extreme environments like northeastern regions where temperatures may drop below -30°C, -40°C rated fluid is more appropriate. If you prefer simplicity, using -25°C rated fluid is also acceptable. Whether to switch to antifreeze windshield washer fluid in winter: This depends on local temperatures. If winter temperatures are low, the fluid should be replaced with antifreeze before winter arrives to prevent freezing and rendering it unusable. Typically, winter-specific antifreeze windshield washer fluid can ensure it doesn't freeze or damage car components even when outside temperatures drop below -20°C. There is also a special antifreeze type that remains unfrozen at -40°C, suitable for use in extremely cold northern regions.