Where Is It Warm in September?

The Mediterranean holds through September far better than most people expect — Athens and Ibiza in the low eighties, Tenerife at 82 °F, the Greek and Croatian coasts still fully open. Water temperature lags air temperature by about six weeks, which is why September swimming beats June swimming even though the air is cooler.

The Caribbean is warm and worth a caveat: sea temperatures around 88 °F, but September is the statistical peak of the Atlantic hurricane season. The figures on this page describe averages, not risk, and that is one place where the average does not tell you what you need to know.

September is the month the Mediterranean's numbers are at their best and least known. Santorini holds 76 °F air with a 77 °F sea on 8 mm of rain and 353 hours of sun — warmer water than June, drier than May, and after the crowds have gone.

The Caribbean is warmer and much wetter. Montego Bay is 87 °F with an 88 °F sea, but 171 mm of rain, and Cancún 182 mm. Water temperature and storm season are driven by the same heat, which is why September gives you the best swimming and the highest risk in the same figure.

September's dividing line is Labor Day, and it is a hard one. Before it, summer pricing; after it, the quietest and best-value stretch of the northern year. If you are choosing between late August and mid-September, the second is cheaper, emptier and warmer in the water.

Three things move a fare more than the destination does. Book six to eight weeks ahead for short-haul and two to three months for long-haul or peak season — later than that and you are usually paying for someone else's cancellation. Fly midweek: leisure demand clusters on Friday evenings and Sunday returns, and a Tuesday departure is routinely cheaper for the same trip. And shift your dates before you shop for airlines — a day or two either side of a holiday weekend saves more than any loyalty programme. The low fare calendar shows which days are actually cheapest on our busiest routes.

Every temperature on this page is the average daily high for that destination in that month, measured rather than estimated. The sea and rainfall filters come from the same source. Drag either end of the range to change what counts as warm — the list re-sorts instantly, warmest first.