Weather in Cartagena in August

Shoulder season. August sits in between. You will get good days and you will lose some. You should expect rain on 25 days of the month, which is more days wet than dry.

August ranks 12 of 12 — near the bottom of Cartagena's year. January is the month that works, and the swing between the two is 37 points, which is a different holiday rather than a slightly better one.

Rain on 25 of the month's 31 days, 4 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Natural fibres and a second shirt for the day. At 82% nothing dries, including you.

What the averages hide

Averages flatten a month, and this one hides a few things: 15 days top 30 °C — hot spells arrive, but they break; the day barely swings — 2.5 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest August day reached 33.5 °C and the coldest night fell to 25.9 °C, and the wettest single day dropped 56 mm — roughly 35% of the month's rain in one day.

August is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest August on record still delivered 298 mm against 64 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 160 mm average is a reasonable planning figure, not a promise.

Wind is light at 12.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 82%, high enough to notice on the warm days without dominating them.

How August sits in the year

Temperatures hold steady either side: 30.2 °C in July, 30 here, 29.5 in September. Nothing about the timing within the month matters much.

Daylight in August

Cartagena sits close enough to the equator that daylight barely moves all year — 12.5 hours in August, against a range of just 1.2 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

Sea temperature

The sea sits at about 29.1 °C in August — warm enough that the water offers no relief from the heat. The sea peaks at 29.3 °C in October and bottoms out at 27.1 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

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

August in Cartagena versus nearby

If Cartagena is one option among several, the nearby comparison is worth making. Barranquilla is close enough to be a coin toss — within a degree on temperature, 2 days less rain. Medellín is a better bet in August — 4.9 °C cooler, the same number of rain days.

So: August is a compromise. January is 37 points better and is what Cartagena is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Cartagena

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