Brasília month by month, at a glance
Hover each month for the summary. Click to pin it.
Temperature is not the problem here: average highs move between 25.3 and 29.1 degrees all year, and lows between 13.9 and 18.5. What splits the calendar in two is not the thermometer, it is the hygrometer.
01 Two halves and no transition
From October to April it really rains. November accumulates 253.1 millimetres, December 241.1 and March 226. These are afternoon storms, intense and short, that leave the city washed and the cerrado green.
From May to September, by contrast, the rain vanishes. June stops at 3.3 millimetres and July at 1.5, figures that in practice mean whole months without a drop.
The change between halves is abrupt. There is no slow spring: within a couple of weeks you go from daily storms to permanently clear skies, or the other way round.
Key moments at a glance
26.9 mm of rain and humidity still at 65 per cent.
43.5 per cent average humidity and frequent dry-air alerts.
The hottest month, at 29.1 degrees, and still very little rain.
253.1 mm in afternoon storms, with the city at its greenest.
02 August and September, the hard months
The humidity figures explain why the dry season here is experienced as a health issue and not as good weather. July drops to 51 per cent on average, August to 43.5 and September to 46.4.
Those averages hide worse peaks. On the driest days, stations in the region record single-digit minimums, and the authorities issue alerts advising hydration, avoiding outdoor exercise in the middle of the day and humidifying indoor spaces.
Add smoke to that. At the end of the dry season fires in the cerrado are frequent, and in August and September the horizon can appear veiled for days.
03 The rainy season is friendlier than it looks
Two hundred and fifty millimetres in November look alarming on paper, but the pattern is predictable: clear mornings, clouds building at midday and a strong storm in mid-afternoon lasting an hour or two.
With a morning plan and a flexible afternoon, the wet half is perfectly comfortable. On top of that the air is clean, humidity is around 75 per cent and the cerrado around the city is green.
There is an aesthetic compensation almost nobody mentions: the storms on this plateau produce enormous skies, with clouds you can see coming from a long way off because the horizon is so flat.
04 The light, an argument in itself
This is a city of flat horizon, open sky and white buildings, and that makes light part of the trip. Sunrises and sunsets are long and very clean, especially in the dry season.
If you are travelling for the architecture, plan around that light: the façades on the central axis work best early and late, when the sun comes in from the side and the volumes gain relief.
Midday, by contrast, is the worst moment: vertical sun, scant shade, overheated concrete and no protection on the esplanades. It is the hour to step into a museum.
Here winter is not measured in degrees, it is measured in percentage of humidity.
05 How to choose
The best month of the year is May: the rain has stopped, at 26.9 millimetres, humidity is still around 65 per cent and the cerrado is still green. April and October are the other two hinges that work well.
Avoid August and September if you can: very dry air, smoke from fires on the horizon and the year's peak heat. And if you go in the rainy season, plan for the morning and leave the afternoon open.
