ERA5 almanac — 8 years of real data

Cartagena in January

Cartagena in January: rain frequency data not yet backfilled for this month, 89°F average high, 51% of days historically clear (n=248, ERA5 2018–2025).

Cartagena in January is a mixed month for sun: 51% of days historically clear (n=248, avg high 89°F). The outcome varies year to year — check the early/late split below. Historical average, not a forecast.

What you are reading: 8-year historical averages from the ERA5 reanalysis, not a forecast. A month that is historically 90% clear can still be overcast on your specific trip. For this week’s actual forecast, see the live Cartagena page. Both can be true at once: “historically strong in this month; this particular week is not.” We label which is which.

Early vs. Late January

Clear-sky percentage for Cartagena in January, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period	% Clear days	Sample (n)	Avg high
Early January 1st–15th	40%	n=120	89°F
Late January 16th–end	62%	n=128	89°F
Full month average	51%	n=248	89°F

Bottom line

Cartagena in January is genuinely mixed: 51% of days historically clear (n=248), avg high 89°F — roughly even odds. The two halves differ materially (40% early, 62% late) — favour the late half of the month. The outcome varies year to year; don't book if you need guaranteed sun.

Every month in Cartagena

Compare across all months with data. Numbers are historical clear-sky %.

Historical clear-sky % for Cartagena, all months, ERA5 2018–2025.
Month	% Clear	Sample (n)
January ← this page	51%	n=248	All destinations →
February	56%	n=226	All destinations →
March	35%	n=248	All destinations →
April	10%	n=240	All destinations →
May	5%	n=248	All destinations →
June	4%	n=240	All destinations →
July	4%	n=248	All destinations →
August	3%	n=248	All destinations →
September	1%	n=240	All destinations →
October	1%	n=248	All destinations →
November	4%	n=240	All destinations →
December	26%	n=248	All destinations →

Frequently asked

Is Cartagena good for sun in January?

It's mixed. Cartagena in January is clear on 51% of days historically (avg high 89°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

→ Cartagena live forecast — this week’s actual 7-day weather, not historical
→ Best destinations in January — all destinations ranked by January clear-sky %
→ All destinations
→ Raw data (JSON) — buckets, n, source

All percentages are historical averages from the ERA5 reanalysis via Open-Meteo, 8 full years (2018–2025). “Clear” means avg high ≥ 72 °F, precipitation < 1 mm, and a non-precipitation weather code. This is history, not a forecast. The live 7-day outlook for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.