Weather in Belém in September

A hard month. September is a hard month in Belém, and worth planning around. You should expect rain on 16 days of the month, which is more days wet than dry.

Belém barely has seasons. September scores 44 out of 100 against a best of 49 in February — a gap small enough that the month you choose matters far less here than the week you choose.

This is persistent light rain rather than storms: 16 wet days but only 2 heavy ones. It rarely cancels anything outright, and it rarely fully clears either. A jacket beats an umbrella. Pack for 33.2 °C days and 24.7 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 30 days top 30 °C, making the heat continuous rather than occasional. Across the twenty years measured, the hottest September day reached 36.2 °C and the coldest night fell to 22.8 °C, and the wettest single day dropped 25 mm — roughly 33% of the month's rain in one day.

September is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest September on record still delivered 165 mm against 35 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 75 mm average is a reasonable planning figure, not a promise.

Wind is light at 2.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 73%.

How September sits in the year

Temperatures hold steady either side: 31 °C in August, 33.2 here, 33.7 in October. Nothing about the timing within the month matters much.

Daylight in September

Belém sits close enough to the equator that daylight barely moves all year — 12.1 hours in September, against a range of just 0.2 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

An inland climate

Despite being inland, the year stays fairly even: 9.7 °C between the year's warmest afternoons and coldest nights.

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 Belém versus nearby

If Belém is one option among several, the nearby comparison is worth making. Fortaleza is a better bet in September — 3.2 °C cooler, 15 days less rain. Manaus is close enough to be a coin toss — within a degree on temperature, 2 days less rain.

So: September is effectively as good as it gets here — 5 points behind February, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Belém

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