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Nerd mode: every forecast, readouts, filters and range & bearing for weather enthusiasts

This week’s weatherRio de Janeiro, Brazil

Rain is likely in Rio de Janeiro on Tuesday

7 in 10 of NOAA’s 31 GEFS forecasts bring measurable rain to Rio de Janeiro Mon 9 p.m.–3 a.m. GMT-3; 3 in 10 bring 2.5 mm or more Tue 3–9 p.m.

NOAA GEFS, 31 forecasts · Mon 28 Sep 18Z run · updated Mon., Sept. 28, 8:03 p.m. GMT-3 · times are Rio de Janeiro’s (GMT-3)

See it on the globe For warnings, follow your national weather service.

Quick answers

Will it rain in Rio de Janeiro this week?
The best chances of measurable rain: Tuesday (7 in 10 forecasts, 9 p.m.–3 a.m.); Wednesday (5 in 10 forecasts, 3–9 p.m.); Thursday (nearly all forecasts, 3–9 p.m.); Friday (nearly all forecasts, 3–9 a.m.). Times are GMT-3.
How much rain will Rio de Janeiro get this week?
By Mon., Oct. 5, 3 p.m. GMT-3 (the end of the forecast), the middle forecast has 40 mm of rain and melted snow, counting from Mon 9 p.m. 9 in 10 forecasts bring 25 mm or more in total; 4 in 10 forecasts bring 51 mm or more.
How windy will it get in Rio de Janeiro?
No strong gusts: fewer than 1 in 10 forecasts have gusts over 48 km/h at any of the six-hourly times. The middle forecast’s strongest gust is 26 km/h, Sun., Oct. 4, 3 p.m. Checked every six hours, so a brief peak can fall between.
How warm or cold will it be in Rio de Janeiro?
At the six-hourly times, the middle forecast runs from 20°C (Sat 3 a.m.) to 31°C (Wed 3 p.m.) GMT-3. The day’s real high and low can fall between those times.
Are any storms heading for Rio de Janeiro?
No storm Stormlines tracks has 1 in 10 forecasts passing its centre within 160 kilometres of Rio de Janeiro this week.

Chance of rain, six hours at a time

Mon 9 p.m.–3 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.9 mmTue 3–9 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneTue 9 a.m.–3 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneTue 3–9 p.m.: 5 in 10 forecasts with measurable rain; middle forecast almost noneTue 9 p.m.–3 a.m.: 3 in 10 forecasts with measurable rain; middle forecast almost noneWed 3–9 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 9 a.m.–3 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 3–9 p.m.: 5 in 10 forecasts with measurable rain; middle forecast almost noneWed 9 p.m.–3 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.7 mmThu 3–9 a.m.: 8 in 10 forecasts with measurable rain; middle forecast 0.6 mmThu 9 a.m.–3 p.m.: 5 in 10 forecasts with measurable rain; middle forecast almost noneThu 3–9 p.m.: nearly all forecasts with measurable rain; middle forecast 3.8 mmThu 9 p.m.–3 a.m.: nearly all forecasts with measurable rain; middle forecast 3.7 mmFri 3–9 a.m.: nearly all forecasts with measurable rain; middle forecast 2.8 mmFri 9 a.m.–3 p.m.: nearly all forecasts with measurable rain; middle forecast 2.7 mmFri 3–9 p.m.: nearly all forecasts with measurable rain; middle forecast 2.0 mmFri 9 p.m.–3 a.m.: 9 in 10 forecasts with measurable rain; middle forecast 1.6 mmSat 3–9 a.m.: 8 in 10 forecasts with measurable rain; middle forecast 1.0 mmSat 9 a.m.–3 p.m.: 8 in 10 forecasts with measurable rain; middle forecast 0.9 mmSat 3–9 p.m.: 8 in 10 forecasts with measurable rain; middle forecast 1.1 mmSat 9 p.m.–3 a.m.: 5 in 10 forecasts with measurable rain; middle forecast almost noneSun 3–9 a.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneSun 9 a.m.–3 p.m.: 3 in 10 forecasts with measurable rain; middle forecast almost noneSun 3–9 p.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneSun 9 p.m.–3 a.m.: 5 in 10 forecasts with measurable rain; middle forecast 0.3 mmMon 3–9 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneMon 9 a.m.–3 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.4 mm

Each bar is the share of the 31 forecasts with measurable rain or melted snow in that six hours; the darker the bar, the more forecasts agree. Local days, GMT-3.

The week, day by day

DayChance of rain2.5 mm or moreTotal by day’s endStrongest gustTemperature
Mon 28 (rest of day)–––26 km/h22°C
Tue 297 in 103 in 102.5 mm · <1 in 1022 km/h21°C–28°C
Wed 305 in 102 in 104.1 mm · 1 in 1021 km/h23°C–31°C
Thu 1nearly all6 in 1011 mm · 5 in 1023 km/h21°C–24°C
Fri 2nearly all6 in 1024 mm · 9 in 1020 km/h20°C–21°C
Sat 39 in 105 in 1035 mm · nearly all23 km/h20°C–22°C
Sun 45 in 102 in 1036 mm · nearly all26 km/h21°C–28°C
Mon 5 (part)6 in 102 in 1040 mm · nearly all19 km/h23°C–26°C

Chances are the highest in any six hours of the day. “Total by day’s end” is the middle forecast’s running total since Mon 9 p.m., and the share of forecasts with 13 mm or more by then; totals aren’t added up day by day, because the middle forecast of each day isn’t the same forecast. Gusts and temperatures are read every six hours.

Storms near Rio de Janeiro

No storm Stormlines tracks has 1 in 10 forecasts passing its centre near Rio de Janeiro this week. Every storm we’re tracking →

About these numbers

They come from one source, NOAA’s Global Ensemble Forecast System (GEFS): 31 runs of the same model, each started slightly differently, read at Rio de Janeiro’s coordinates on a grid about 55 km (35 miles) apart. “8 in 10 forecasts” means 8 in 10 of those runs. Nothing is adjusted for local effects such as coasts, lakes, hills or city heat, so the numbers can differ from your local official forecast, especially for snow and showers.

“Measurable rain” counts rain or melted snow in a six-hour period. Not an official forecast: follow your national weather service for warnings and decisions. How the forecasts are read: how to read the maps and the glossary.

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