Sugar begins to dissolve in water at any temperature, but the rate and efficiency of dissolution increase with temperature. Typically, at room temperature, which is around 20°C (68°F), sugar dissolves moderately well. However, as the temperature rises, the solubility of sugar in water improves significantly.
For example, at 100°C (212°F), which is the boiling point of water, sugar can dissolve much more readily compared to cooler temperatures. Hot water molecules move faster, allowing sugar molecules to break apart and integrate into the solution more efficiently. This is why when making things like syrups or sweetening tea, using hot water aids in dissolving the sugar quickly.
In summary, while sugar can dissolve at any temperature, higher temperatures enhance the rate and quantity of sugar that can be dissolved in water.