September weather in Malta: still warm, with rain that picks its moments

Two similar averages, two different months

September in Malta is a month of negotiations. Summer would like another swim; autumn would like to make a point. A reassuring monthly temperature average can conceal both arguments taking place within the same four weeks.

At Mosta, Weather.mt’s saved forecasts produced a monthly mean of 25.1°C in September 2024 and 25.4°C in September 2025. On that single measure, the two months look remarkably similar. The average daily highs were 27.6°C and 27.9°C, and the average daily lows were 22.8°C and 23.1°C.

But September 2024 began much hotter, had more 30-degree days and included stronger winds. September 2025 was more restrained at the hot end yet delivered a higher forecast rainfall total at Mosta. The monthly mean is useful; it is also rather good at keeping secrets.

In 2024, summer stayed for the opening act

Mosta’s first ten days of September 2024 averaged 27.9°C across the hourly series. The last ten averaged 23.8°C: a drop of about 4.1°C between those two parts of the month. The highest value reached 33.3°C on 6 September, and seven days reached at least 30°C.

September 2025 had a gentler contrast. Its first ten days averaged 26.0°C and its final ten averaged 24.1°C, a reduction of about 2.0°C. Only two days at Mosta reached 30°C, with a monthly peak of 30.2°C on 11 September.

The curious result is that the year with the more dramatic early heat did not have the warmer monthly mean. Later conditions pulled the 2024 average down. If you are comparing an early-September stay with one near the end of the month, these profiles tell you considerably more than a single number labelled “September temperature”.

The lowest hourly forecast value at Mosta was 19.9°C in both years, occurring on 18 September 2024 and 27 September 2025. That is another reminder that matching extremes do not make matching months: timing, duration and everything between the extremes still matter.

The 2025 cooling was concentrated in the final third

The first ten days of September 2025 averaged 26.0°C at Mosta, and the middle ten were also about 26.0°C. The final ten averaged 24.1°C. That puts the more noticeable change in the closing section, rather than describing an even decline from the first day onwards.

September 27 belongs to that lower final stretch. Its daily mean was about 21.4°C and its highest hourly temperature 22.9°C, alongside the month’s largest rain amount. The daily mean chart makes the interruption visible without suggesting that all the surrounding dates shared exactly the same conditions.

The 2024 profile started hotter and changed more dramatically, with its first ten-day mean of 27.9°C falling to 23.8°C in the last ten. These are two distinct versions of the transition. A visit near the beginning and one near the end deserve separate attention, particularly when the monthly average is hiding a sizeable difference between them.

More rain can mean fewer rainy days

Mosta’s forecast rainfall total was 26.6 mm in September 2024 and 43.0 mm in September 2025. Yet 2024 had four days with at least 1 mm, while 2025 had only two. The wetter total belonged to the month with fewer qualifying wet days.

The explanation is concentration. On 27 September 2025, the saved hourly forecasts summed to 37.7 mm at Mosta—almost 88% of that month’s total. Another 4.0 mm appeared on 24 September, leaving only small amounts across the remaining dates. One large episode dominated the monthly figure.

In 2024, the rain was distributed more widely. The largest daily amount was 11.4 mm on 9 September, followed by 6.8 mm on the 19th and 4.6 mm on the 23rd. Those different schedules matter. A high monthly total does not mean that rain occupied most of the month, and a relatively modest total can still include several interrupted days.

This is why “rainy but warm” needs a little unpacking. September can retain plenty of warmth while a handful of rain episodes do most of the work. The useful questions are how often rain appears, how much is concentrated into one date and where the forecast puts it—not whether the month deserves a single gloomy adjective.

2024 had the livelier wind forecast

Average hourly wind speed at Mosta was 5.6 m/s in September 2024, compared with 4.2 m/s in 2025. The maximum hourly speeds were 14.1 m/s and 9.1 m/s respectively: Beaufort force 7 against force 5.

Five dates in the 2024 Mosta series reached at least Beaufort force 6. None did so in the 2025 series. These are wind-speed values, rather than gust measurements, but they establish a clear difference in the forecast character of the two months.

A warm temperature reading is therefore only one part of an outdoor plan. Wind direction, exposure and the current sea forecast matter too. An attractive air temperature does not certify swimming conditions, and an umbrella’s opinion of a breezy afternoon is rarely diplomatic. For a future beach day, check the live forecast rather than borrowing the calmer year from this comparison.

A shared warming difference, but local rain totals

The small increase in the 2025 monthly mean appears at all six matched points. Sliema moved from 25.3°C to 25.7°C, Marsaxlokk from 25.6°C to 25.8°C, Victoria in Gozo from 25.3°C to 25.7°C and Comino from 25.8°C to 26.2°C. Mosta and Dingli showed increases of roughly 0.3°C and 0.2°C.

Rain did not follow one uniform island-wide increase. Marsaxlokk’s total fell from 26.1 mm to 20.5 mm, while Comino’s rose from 27.1 mm to 50.7 mm. The Victoria point moved from 38.5 mm to 35.9 mm. Mosta’s wetter 2025 total should therefore remain a Mosta finding, rather than being promoted into a claim about every part of Malta and Gozo.

These point forecasts are useful for comparing the same places through time. They are not a dense network of rain gauges, and small differences between nearby model points should not be oversold. The interesting pattern is the combination of broadly similar warmth with rainfall that varies much more sharply by date and location.

August and September changed places between the years

The summer-to-autumn step at Mosta was about 2.8°C in 2024: August’s mean of 27.9°C became September’s 25.1°C. In 2025 the step was around 1.0°C, from 26.4°C to 25.4°C. The transition therefore started from a cooler August but ended with a slightly warmer September mean in 2025.

Rain also became more prominent between the two months. The full Mosta forecast totals changed from 4.8 mm in August to 26.6 mm in September 2024, and from 1.3 mm to 43.0 mm in 2025. The daily bars show why the latter increase should still be understood as a few episodes rather than a continuous month of rain.

The combined comparison is more useful than asking which month is simply better. August and September offered different balances of warmth, overnight conditions, rain and wind. Your preferred day out might value those parts differently. The archive supplies concrete examples; the current forecast tells you which version of the season is approaching your particular date.

The warm, wet and transitional dates make a better picture

September 6, 2024 supplies the 33.3°C heat example. September 9, 2024 adds the 11.4 mm daily rain amount. September 27, 2025 supplies the more concentrated 37.7 mm episode and a much cooler daily temperature profile. Together they give the month several different faces.

The dates also help explain why a rain total and a hot-day count should not be asked to tell the same story. The warmest hourly value can be long gone by the time the largest rain episode appears. A small set of notable dates makes that sequence easier to follow than a collection of disconnected extremes.

Start with the linked examples, then compare the same hours on adjacent dates if you want to follow the change. That approach is especially useful when looking back at a visit. September’s main appeal as an archive story is its movement between conditions, not the possibility of awarding the whole month one permanent description.

The September lesson: look beyond the average

Our two pilot years capture two versions of the September transition. In 2024, strong early heat gave way to a larger temperature decline, with windier conditions and several separate rain days. In 2025, the temperature curve was steadier and the Mosta rain total was dominated by one late-month episode.

For anyone asking what Malta is like in September, the archive offers a useful answer: the month can contain plenty of warmth, but its early and late weeks need not resemble each other. Rainfall totals, wet-day counts and wind tell different parts of the story. Read them together, and September becomes much more understandable—even if it still refuses to dress for just one season.

Use the archive tool below to inspect a particular date, or compare this article with August to see how the two months differed within each year. For an upcoming trip, check the current forecast close to departure. An archive is excellent at explaining yesterday; tomorrow remains a separate appointment.

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