Bands, and verify before booking. The honest version of the trade, rather than the marketing one.
August and September are the cheapest. Room rates on both sides of the bay hit their annual floor, sometimes at half what the same room costs in February. September in particular has the emptiest weeks of the year, which means walk-ins work and morning tours have space the day before. What you give up: a heat index that regularly passes a hundred by early afternoon, humidity that does not relent overnight, the statistical peak of hurricane season, and the start of the king-tide windows.
The compensation nobody mentions. From August the city's fixed-price restaurant promotion runs, which in 2026 extended through 31 October at published prices in the region of $40 for lunch and $50 to $65 for dinner. It makes the most expensive part of a Miami trip — eating well — the cheap part, and it is over before the winter season starts. Confirm the current dates and prices before you plan around it.
Late April, May and the first half of November are the value windows. Prices well off peak, water warm, light long, no festival distorting the city and, in the November case, the humidity already broken. These are the weeks to take if the aim is a workable trip rather than a status weekend.
February and March are the most expensive and the most pleasant, in that order. You are paying for the absence of a storm hour, and it is a real thing to pay for. Just know that is what the money is buying.
Where the savings actually come from. Not the season, in most cases. Staying on the side of the bay where you want to spend your evenings removes a causeway crossing from every day of the trip, which saves more than the difference between a July room and a February one.