Weather in Cartagena in September

Prime time. If you get to pick your dates, September is the one. Highs average 28 °C, lows 21.8 °C, and rain falls on 5 days — nothing in the month is working against you.

Cartagena barely has seasons. September scores 86 out of 100 against a best of 95 in May — a gap small enough that the month you choose matters far less here than the week you choose.

Rain falls on only 5 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: 4 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 36.7 °C and the coldest night fell to 15 °C, and the wettest single day dropped 62 mm — roughly 200% of the month's rain in one day.

This is the volatile part. September rainfall has ranged from 4 mm to 105 mm across the twenty years measured — a 101 mm spread around an average of 31 mm. The average is real but almost no individual September looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 11.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 69%.

How September sits in the year

The month is on the way down: 2.8 °C cooler than August, with October dropping another 3.2 °C. The first week and the last are not the same trip.

Daylight in September

12.5 hours of daylight, losing 1.2 hours across the month. That is between Cartagena's extremes of 14.7 and 9.6 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 24.4 °C in September — warm enough to stay in as long as you like. This is the warmest the water gets all year.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Cartagena versus nearby

If Cartagena is one option among several, the nearby comparison is worth making. Murcia is the weaker option in September — 3.2 °C warmer, the same number of rain days. Valencia is the weaker option in September — 2.5 °C warmer, 3 days more rain.

So: September works, with May the better month by 9 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Cartagena

See all twelve months in Cartagena, or where else to go in September.