What is considered the best temperature for effective hand washing?

Warm water is considered the best temperature for effective hand washing because it helps to dissolve oils and debris more effectively than cold water. The warmth of the water aids in producing a lather with soap, increasing the mechanical action needed to remove dirt, bacteria, and viruses from the hands' surfaces. Additionally, warm water is generally more comfortable for prolonged washing, which can encourage individuals to wash their hands for the recommended 20 seconds or more.

While hot water can be effective, it may also lead to skin irritation or dryness, potentially discouraging frequent hand washing. Cold water, on the other hand, is less effective at dissolving substances, making it less suitable for thorough cleansing. Room temperature water, while better than cold water, does not have the same level of effectiveness as warm water in promoting a good lather and facilitating thorough cleaning. This makes warm water the optimal choice for hand washing in terms of both effectiveness and comfort.