The year in Naples, month by month
All the figures are Naples': 1,008.2 millimetres of rain a year over 86.5 days and 2,375.4 hours of sunshine. The scoring crosses three things: how much water falls, how much light there is and how many people are there with you.
April is the month when half the world decides to visit Pompeii, Naples and the Amalfi coast. The logic looks impeccable: Mediterranean spring, mild temperatures, before July's heat and crowds. The climate table disagrees with part of that reasoning.
In April 98.6 millimetres of rain fall in Naples. In January, 92.1. And the number of rainy days is the same in both months: 9.3. In other words, spring's star month is wetter than the depths of winter.
01 Ninety-eight millimetres in April
It is worth setting out the full list, because it upends the intuition. Naples' wettest months are, in this order: November with 152.1 millimetres, October with 135.5, December with 112.0 and April with 98.6. Then come February with 95.3, January with 92.1, September with 88.9 and March with 77.9.
April is therefore the fourth wettest month of the year. And March, usually dismissed as too early, is the least wet month of the entire wet half-year. Spring here does not work the way it is supposed to.
The annual total is 1,008.2 millimetres spread over 86.5 rainy days, with 2,375.4 hours of sunshine. It is a textbook Mediterranean climate in quantity, but with a distribution concentrated outside summer in a very marked way.
02 The water is in the autumn
The year's real centre of gravity is October and November. Between them 287.6 millimetres fall, almost 29 % of the whole year, and they are also the two months with the most rainy days after January: 8.5 and 10.2.
The reason is the usual Mediterranean one: the sea is still warm after summer, the air begins to cool and the difference feeds storms. In Campania the relief is added, with 34 % mountain and 51 % hill, forcing moist air to rise and multiplying rainfall.
Light falls with it. November gives 126.0 hours of sunshine and December 105.4, the year's minimum. Between December and July there is a difference of more than two hundred hours a month, almost seven hours of sunshine a day.
03 And the summer is a drought
At the opposite end, July receives 28.5 millimetres over 2.4 rainy days and accumulates 313.1 hours of sunshine, both record figures for the year in their respective columns. August follows with 35.5 millimetres over 3.7 days and 294.5 hours.
The figure separating July from November is more than fivefold: 28.5 millimetres against 152.1. That means the rain variable decides the trip far more than temperature, because from one month to another it changes by a factor of five while the thermometer moves twelve degrees.
The price of the dry summer is heat and crowds. August gives average highs of 31.0 degrees and nights of 21.4, with an absolute record of 40.0 degrees. Walking a shadeless archaeological site with those figures is a decision, not a plan.
The year's four stretches
From 92.1 to 112.0 millimetres a month over about nine days, with sunshine between 105.4 and 127.6 hours. Highs stay at 13.4 to 14.3 degrees. It is not properly cold, but this is the darkest stretch of the year.
77.9 and 98.6 millimetres over 8.6 and 9.3 days. April is the fourth wettest month of the year and rains more than January, even though light climbs to 189.0 hours and highs to 19.4 degrees. It is also the busiest time at the archaeological sites.
From 88.9 down to 28.5 millimetres, with rainy days between 6.1 and 2.4 and sunshine between 234.0 and 313.1 hours. Highs of 23.6 to 31.0 degrees. May and September are the good extremes; July and August the hot, crowded ones.
135.5 and 152.1 millimetres over 8.5 and 10.2 days: between them they make up almost 29 % of the year's rain. Sunshine falls from 189.1 to 126.0 hours and highs from 23.0 to 18.3 degrees.
04 Temperature is not the problem
Naples' thermometer is benign all year. The average high runs from 13.4 degrees in January to 31.0 in August, and the average low from 4.7 to 21.4. There is no month in which the average high drops below 13 degrees.
Extremes exist but they are exceptional: the station has recorded 40.0 degrees in August and −5.6 in January. Neither of those figures describes an ordinary week of travel.
The practical consequence is that in Campania you do not choose the month to avoid cold, because you will not be cold. You choose it to avoid rain and to avoid everybody else, and those two things do not always point to the same month.
05 The other variable: how many people
Here it is worth adding a figure that is not in the climate table. Pompeii received more than four million visitors in 2024, an absolute record, and at the end of that same year a cap of 20,000 daily admissions was introduced along with named tickets.
Those four million are not evenly spread. They concentrate in spring and summer, that is, in precisely April, May, July and August. March and September sit on the edge of the high season with weather that is no worse.
Crossing the two series, the conclusion is awkward for the usual calendar: April combines the fourth wettest month of the year with one of the biggest crowds. It is the worst box in the table, and it is the one most people choose.
06 How to choose the month
If you can go only once, go in May or September. May gives 59.0 millimetres over 6.1 days, 244.9 hours of sunshine and average highs of 23.6 degrees; September gives 88.9 millimetres over 6.1 days, 234.0 hours and 26.8 degrees. Both have half of April's rainy days.
If your only window is spring, choose March over April: 77.9 millimetres over 8.6 days against 98.6 over 9.3. You will have less light — 158.1 hours against 189.0 — and highs of 16.4 degrees instead of 19.4, but less water and considerably fewer people.
And if you have to go in July or August, run the day backwards: sites first thing, shade at midday, coast in the afternoon. With average highs of 31.0 degrees and 313 hours of sunshine a month, rain will not be your problem.
