The year in Split-Dalmatia, month by month
The figures come from the Split station, on Marjan hill, 1991–2020 series: 800.6 millimetres a year over 107.9 days and some 2,699 hours of sun. The scoring crosses rain, rainy days, sunshine and air temperature.
The Mediterranean climate has a reputation for being easy to summarise: dry summer, mild winter. The dry-summer part is true here and then some. The mild-winter part needs qualifying, because what defines the cold half of the year on this coast is not cold.
It is water, and it all arrives at once in autumn.
01 A hundred and twenty millimetres against a hundred and five
The Split station, on Marjan hill, records 119.8 millimetres in November over 11.7 days. The three summer months give 49.2 in June, 24.6 in July and 31.7 in August: 105.5 millimetres between them.
That is, November alone beats the entire summer by fourteen millimetres. And in rainy days the difference is clearer still: 11.7 days in November against 17.5 spread across three summer months.
December is not far behind, with 98.7 millimetres over 11.9 days. Between September and December 380.4 millimetres fall, 47.5 per cent of the annual total, in four months.
A hundred and nineteen point eight millimetres in November and a hundred and five point five in June, July and August together.
02 And September rains more than January
There is one figure that unsettles anyone travelling with the idea that winter is the wet season: September collects 82.3 millimetres and January 72.7. The first month of autumn is wetter than midwinter.
The jump happens from one month to the next. August gives 31.7 millimetres over 4.6 days; September, 82.3 over 8.2. Rainfall multiplies by two and a half and rainy days almost double, with no transition.
The cause is the sea. The Adriatic accumulates heat all summer and in autumn stays warm while the air above begins to cool. That difference feeds convective storms, which is why September and November rainfall is intense and brief rather than soft and prolonged.
03 Three hundred and fifty-nine hours of sun in July
The counterweight to the rainfall distribution is sunshine, and here the figures are among the best in Europe. Split totals some 2,699 hours of sun a year, and July alone contributes 358.7: almost twelve hours a day.
August adds 335.0 and June 317.8. Between May and August 1,289.4 hours accumulate, almost half the year in four months, with relative humidity dropping to 49 per cent in July.
And the collapse is just as abrupt. December comes to 127.9 hours and January to 139.5: barely over four hours of sun a day. The difference between July and December is not one of degrees, it is one of light.
04 Winter, which is not cold but is dark
Winter temperatures are not the problem. January's average maximum is 10.7 degrees and its minimum 5.9; in December, 11.8 and 7.2. Those are the figures of an Atlantic city in northern Spain, not of an inhospitable place.
What changes the experience is the combination of high humidity, closed skies and wind. Relative humidity reaches 65 per cent in November and 61 in January, against July's 49.
And on top of that, life on this coast is designed for outdoors: terraces, seafront promenades, ferries. In winter the whole system runs at half power, with reduced timetables on the islands and fewer boat crossings.
05 Why the rain does not show in the landscape
There is an apparent contradiction worth resolving. Split collects 800.6 millimetres a year, more than many northern European cities, and yet the landscape is that of a dry place: bare rock, low scrub and not a stream in sight.
The explanation is limestone. On karst terrain water does not run on the surface: it filters through fissures and conduits and travels underground. The rain falls and disappears within hours.
That is why the effect of November's 119.8 millimetres is very different from what it would be elsewhere. They do not pool or flood: they fall, they go and they leave the rock wet for a few hours. And that is also why summer, with 24.6 millimetres in July, produces a real drought even though the annual total does not suggest it.
06 How to choose the month
If the trip is about the sea, June to September. July and August give 358.7 and 335.0 hours of sun with 5.1 and 4.6 rainy days, and September holds 246.3 hours and highs of 25.4 degrees even though rain has already tripled.
If the trip is about towns, walking or islands without crowds, May and June are better: 277.9 and 317.8 hours of sun, highs of 23.4 and 28.1 degrees and the landscape still green before July's drought burns it off.
And if you can only go in the cold half, February and March rather than November and December. February gives 63.8 millimetres and March 58.4, against November's 119.8, and sunshine climbs from 151.7 to 195.1 hours instead of falling.
The year's four stretches
From 24.6 to 57.8 millimetres a month over 4.6 to 9.4 days, with 277.9 to 358.7 hours of sun and highs of 23.4 to 31.0 degrees. July and August together add up to 56.3 millimetres: less than half of November.
79.6 to 82.3 millimetres over 8.2 to 9.3 days, with 197.8 to 246.3 hours of sun and highs of 20.5 to 25.4 degrees. Rain has tripled since August and the sea is still warm.
From 63.8 to 119.8 millimetres a month over 9.4 to 11.9 days, with sunshine between 127.9 and 151.7 hours: four or five a day. Highs of 10.7 to 11.8 degrees and humidity at its annual peak.
58.4 to 62.0 millimetres over 9.6 to 10.4 days, but sunshine rises from 195.1 to 221.5 hours and highs from 14.5 to 18.4 degrees. A good time to walk; a bad one to swim.
