Curing is not drying
Paint dries. Concrete cures. Water is not just leaving the mix, it is reacting with the cement inside it, a process called hydration that keeps building strength for weeks after the surface looks set. Lose that water out of the top too early, and a hot sun or a steady wind will take it, and the outer skin of the slab never gains the strength the rest of it does. That is the layer that later dusts underfoot or checks with fine cracks.
That is why the timing at the start matters more than people expect. A slab that loses its water too fast on day one never fully catches up, even though the concrete underneath keeps hardening for weeks. Keeping that moisture in the slab, by covering it, wetting it, or spraying on a curing compound, is what curing actually means in practice.
What curing needs, and for how long
Concrete needs water available at the surface for the hydration reaction to keep going, and it needs that for longer than most people expect. Most new concrete is firm enough to walk on within a day or two, but it is nowhere near full strength yet. Strength keeps building well past that first week and lands close to full around the 28 day mark.
Weather changes the timeline. August concrete and January concrete do not behave the same way, so any real number for how long to keep a slab wet has to come from the mix that went down and the weather it went down in. You get cure instructions for the actual pour instead of a figure copied off a chart, and the whole first month, laid out week by week, lives in our 30 day guide.