Summer is the single best SAT prep window on the calendar, and most students waste it in one of two ways. Either they plan a monster study schedule in June, burn out by July 4th, and quit. Or they promise themselves they will start "soon" and open a prep book for the first time in mid-August.
The plan that works is smaller than the first and earlier than the second: 30 to 45 minutes a day, most days, from mid-June to your test date. That is it. Here is why that is enough, and how to structure it.
Why Summer Beats Every Other Window
During the school year your SAT prep competes with homework, sports, APs, and exhaustion. Whatever time you schedule, school takes a cut of it. In summer, a 40-minute session is actually 40 focused minutes, every day, with a fresh brain. The same daily commitment simply buys more progress in July than it does in March. If you are aiming at the August test, the timing lines up perfectly; October works too and gives you extra runway.
The Shape of the Plan
Late June: Baseline
Take one full-length test to find out where you actually are. Bluebook if you have official tests left, or a Sigma Prep practice test (the first one is free). The output you want is a specific list: which topics, at which difficulty, are costing you points. Not a feeling. A list.
July: Skill Work
This is the bulk of the summer. Daily sessions target the topics from your list, easy and medium difficulty first, because the adaptive test structure makes easy and medium mastery worth more than hard-problem heroics. Every miss gets its video explanation watched and the same topic revisited a few days later.
This is also where Sigma Prep does the navigation for you. After each practice test, it builds a practice set from exactly what you got wrong, and each topic in the practice section is split by difficulty so you can re-drill a weak spot at precisely the level it broke. You are never left asking "what should I do today?" The answer is sitting in your last set of misses.
August: Measure and Tighten
Shift to the test-drill-retest loop: full-length test, review every miss, work the practice set it generates, take a fresh version a week later and confirm the score moved. With 24 full-length tests in 3 versions each, you will not run out of fresh measurements before test day.
The Honest Time Math
Forty minutes a day for ten weeks is roughly 45 hours of focused prep. That is bootcamp-course volume, spread painlessly, for a fraction of the cost, and it still leaves you your summer. The students who show up in August with 100-point jumps are almost never the ones who studied four hours a day for two weeks. They are the ones who never missed more than a day or two in a row.