The short answer: weekly in spring and fall, and every 10–14 days during the driest weeks of summer — but the more useful rule is to mow based on growth, not the calendar.
Spring: Weekly, and Watch the Height
Spring rain and mild temperatures push fast growth. Weekly mowing keeps up without cutting more than about a third of the blade length at once — scalping a fast-growing spring lawn stresses it right when it should be building strength.
Summer: Slow Down and Mow Higher
Growth naturally slows in the dry heat of July and August, and this is where the most common mistake happens: cutting the lawn shorter to "clean it up" for summer. Do the opposite. Raising the mower height in summer shades the soil, keeps roots cooler, and reduces how much water the lawn needs to stay green through the dry stretch.
Fall: Back to Weekly, Then Tapering
Returning rain and cooling temperatures kick growth back into gear — often the second-strongest growth period of the year. Weekly mowing typically resumes until growth slows again heading into winter, at which point visits taper off rather than stopping abruptly.
The One Rule That Matters More Than Frequency
Never remove more than about a third of the grass blade in a single cut, regardless of season. If a lawn has gotten away from you, bring it down gradually over two or three mows instead of scalping it in one pass — a single hard scalp opens the door for weeds and stresses the lawn more than a slightly-too-long week ever would.