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

This week’s weatherTokyo, Japan

Rain is likely in Tokyo on Tuesday

Nearly all of NOAA’s 31 GEFS forecasts bring measurable rain to Tokyo Tue 9 a.m.–3 p.m. GMT+9; nearly all bring 2.5 mm or more.

NOAA GEFS, 31 forecasts · Mon 28 Sep 18Z run · updated Tues., Sept. 29, 8:03 a.m. GMT+9 · times are Tokyo’s (GMT+9)

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

Quick answers

Will it rain in Tokyo this week?
The best chances of measurable rain: Tuesday (nearly all forecasts, 9 a.m.–3 p.m.); Wednesday (9 in 10 forecasts, 9 p.m.–3 a.m.); Thursday (7 in 10 forecasts, 9 p.m.–3 a.m.); Sunday (4 in 10 forecasts, 9 p.m.–3 a.m.). Drier: Fri (fewer than 2 in 10 forecasts in any six hours). Times are GMT+9.
How much rain will Tokyo get this week?
By Tues., Oct. 6, 3 a.m. GMT+9 (the end of the forecast), the middle forecast has 43 mm of rain and melted snow, counting from Tue 9 a.m. 8 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 Tokyo?
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 22 km/h, Fri 3 a.m. Checked every six hours, so a brief peak can fall between.
How warm or cold will it be in Tokyo?
At the six-hourly times, the middle forecast runs from 19°C (Tue 9 p.m.) to 26°C (Thu 3 p.m.) GMT+9. The day’s real high and low can fall between those times.
Are any storms heading for Tokyo?
No storm Stormlines tracks has 1 in 10 forecasts passing its centre within 160 kilometres of Tokyo this week.

Chance of rain, six hours at a time

Tue 9 a.m.–3 p.m.: nearly all forecasts with measurable rain; middle forecast 10 mmTue 3–9 p.m.: nearly all forecasts with measurable rain; middle forecast 7.7 mmTue 9 p.m.–3 a.m.: 9 in 10 forecasts with measurable rain; middle forecast 2.2 mmWed 3–9 a.m.: 5 in 10 forecasts with measurable rain; middle forecast 0.3 mmWed 9 a.m.–3 p.m.: 4 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 0.6 mmThu 3–9 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.7 mmThu 9 a.m.–3 p.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneThu 3–9 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 9 p.m.–3 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneFri 3–9 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneFri 9 a.m.–3 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneFri 3–9 p.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneFri 9 p.m.–3 a.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneSat 3–9 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 9 a.m.–3 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 3–9 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 9 p.m.–3 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneSun 3–9 a.m.: 3 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.: 3 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 almost noneMon 3–9 a.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.6 mmMon 9 a.m.–3 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.7 mmMon 3–9 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.9 mmMon 9 p.m.–3 a.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+9.

The week, day by day

DayChance of rain2.5 mm or moreTotal by day’s endStrongest gustTemperature
Tue 29 (rest of day)nearly allnearly all19 mm · 8 in 1019 km/h19°C–21°C
Wed 309 in 104 in 1022 mm · 9 in 1019 km/h19°C–22°C
Thu 17 in 102 in 1027 mm · 9 in 1018 km/h20°C–26°C
Fri 22 in 10<1 in 1027 mm · 9 in 1022 km/h21°C–24°C
Sat 32 in 10<1 in 1027 mm · 9 in 1018 km/h19°C–24°C
Sun 44 in 101 in 1029 mm · 9 in 1021 km/h19°C–23°C
Mon 56 in 104 in 1040 mm · nearly all19 km/h19°C–21°C
Tue 6 (part)6 in 103 in 1043 mm · nearly all19 km/h19°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 Tue 9 a.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 Tokyo

No storm Stormlines tracks has 1 in 10 forecasts passing its centre near Tokyo 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 Tokyo’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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