Key takeaways
- June, July and August together average almost no rain. Weather is not what shortens a summer day here.
- The sea lags the air by about two months, so September swims warmer than June and often better than July.
- The lagoon faces north west. A strong blow makes it uncomfortable and can move a small boat's plans.
- Late May into June, and September into early October: warm water, workable weather and a fraction of the boats.
What the numbers say
Malta is dry and hot in summer and wet and mild in winter, and the figures are unusually clear-cut. July averages a couple of millimetres of rain across the whole month; October averages nearly a hundred. Daily highs run from around sixteen degrees in midwinter to thirty-one in August.
For a boat trip that means summer weather is close to a non-issue in the ordinary sense. You are not going to be rained off in July. What you might be is blown off, and that is a different question that no temperature chart answers.
The other thing the chart does not show is the sea, which behaves quite differently from the air above it and is the number that actually decides whether a swimming trip is worth taking in a given month.
The sea, which lags behind
Water warms and cools far more slowly than air, and around Malta the sea runs roughly two months behind the calendar. It is at its coldest in February and March, well after the shortest day, and at its warmest in late August and September, well after the hottest air.
This is the single most useful thing to know when choosing a month. June looks like peak summer on an air-temperature chart and the sea is still catching up. September looks like the end of the season and the water is at its best of the year.
By October the sea is still comfortably swimmable for most people even as the air cools and the rain returns, which makes early October one of the quietly excellent times to be on a boat here.
The channel with some weather on it, which is what actually moves a small boat's plans
Wind, and what it does to a small boat
The Blue Lagoon is a channel open to the north west. In a strong wind from that quarter it becomes choppy and unpleasant, the anchored boats roll, and the clarity suffers as the bottom is stirred up.
A large ferry copes with this. A small private boat is more affected, which means a charter is more likely to be shortened, moved to a sheltered part of the coast, or rescheduled. That is not a flaw in the product; it is the trade for having a boat small enough to enter a cave.
The practical response is to book early in your stay rather than on your last day, so a blown-out morning becomes a different morning rather than a missed trip.
Month by month
April and early May are lovely on land and cool in the water. The island is green, the light is good, the sea is around eighteen degrees and swimming is brisk rather than pleasurable. Boats run, and the day is more about the coast than the swimming.
Late May and June are where it turns. The water becomes genuinely warm, the days are long, and the crowds have not yet reached their peak. For many visitors this is the best combination of the year.
July and August are hot, dry, crowded and busy on the water. Everything runs, everything is full, and the early-hour strategy matters more in these two months than in all the others put together.
2 mm
July averages about two millimetres of rain across the whole month, so wind rather than weather is what shapes a summer day here.
July and August, fairly
One thing worth saying about July and August: they are not bad months. They are the months everybody comes, which is a different complaint. The water is warm, the weather is reliable, and the only real problem is one that an early departure solves.
The hottest months are also the driest and the most reliable, and for a family tied to school holidays they are the only option. Nothing about them is a compromise except the number of other people, and that is a problem of hour rather than of month.
The autumn window, and winter after it
September is the month experienced visitors pick. The sea is at its warmest, the air has come off its peak at around twenty-eight degrees, the school holidays have ended and the bay is noticeably quieter than in August. The rain begins to return but is still not a serious factor.
October keeps the warm sea and loses the certainty. It is the wettest month of the year here after the winter, the days shorten, and the season begins winding down. On a good October day the lagoon is close to perfect and nearly empty.
By November the water is cooling in earnest, the weather is unsettled and the charter season is largely over. What remains is the ferry, a colder swim for the committed, and an island that has gone back to belonging to nobody. Comino in winter is a different island: empty, green, windswept and rather beautiful. The sea sits around fifteen or sixteen degrees, which is swimmable for the determined and nobody else, and the weather is genuinely changeable.
Choosing a month
If you want the warmest water and the quietest bay, go in September. If you want the longest days and green landscape, go in late May or June. If you can only come in July or August, go early in the morning and take the four-hour block so the boat can escape the crowd.
And whichever month you choose, keep a spare day in the itinerary. Wind is the only thing on this coast that will actually stop you, it rarely lasts more than a day or two, and a booking made early in a trip has somewhere to move to.
