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

This week’s weatherSapporo, Japan

Rain is likely in Sapporo on Tuesday

9 in 10 of NOAA’s 31 GEFS forecasts bring measurable rain to Sapporo Tue 9 a.m.–3 p.m. GMT+9.

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

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

Quick answers

Will it rain in Sapporo this week?
The best chances of measurable rain: Tuesday (9 in 10 forecasts, 9 a.m.–3 p.m.); Wednesday (7 in 10 forecasts, 9 p.m.–3 a.m.); Thursday (nearly all forecasts, 9 a.m.–3 p.m.); Friday (9 in 10 forecasts, 3–9 p.m.). Times are GMT+9.
How much rain will Sapporo get this week?
By Tues., Oct. 6, 3 a.m. GMT+9 (the end of the forecast), the middle forecast has 30 mm of rain and melted snow, counting from Tue 9 a.m. 6 in 10 forecasts bring 25 mm or more in total; 2 in 10 forecasts bring 51 mm or more.
How windy will it get in Sapporo?
Gusts over 48 km/h: 8 in 10 forecasts at Fri 3 p.m. GMT+9. The middle forecast’s strongest gust is 54 km/h, Fri 3 p.m. Checked every six hours, so a brief peak can fall between.
How warm or cold will it be in Sapporo?
At the six-hourly times, the middle forecast runs from 8°C (Sun 3 a.m.) to 18°C (Wed 3 p.m.) GMT+9. The day’s real high and low can fall between those times.
Are any storms heading for Sapporo?
No storm Stormlines tracks has 1 in 10 forecasts passing its centre within 160 kilometres of Sapporo this week.

Chance of rain, six hours at a time

Tue 9 a.m.–3 p.m.: 9 in 10 forecasts with measurable rain; middle forecast 1.5 mmTue 3–9 p.m.: 8 in 10 forecasts with measurable rain; middle forecast 0.6 mmTue 9 p.m.–3 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.3 mmWed 3–9 a.m.: 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.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 9 p.m.–3 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 3–9 a.m.: 9 in 10 forecasts with measurable rain; middle forecast 1.2 mmThu 9 a.m.–3 p.m.: nearly all forecasts with measurable rain; middle forecast 8.9 mmThu 3–9 p.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneThu 9 p.m.–3 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.5 mmFri 3–9 a.m.: 9 in 10 forecasts with measurable rain; middle forecast 0.9 mmFri 9 a.m.–3 p.m.: 9 in 10 forecasts with measurable rain; middle forecast 1.2 mmFri 3–9 p.m.: 9 in 10 forecasts with measurable rain; middle forecast 0.9 mmFri 9 p.m.–3 a.m.: 9 in 10 forecasts with measurable rain; middle forecast 0.6 mmSat 3–9 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.6 mmSat 9 a.m.–3 p.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.4 mmSat 3–9 p.m.: 5 in 10 forecasts with measurable rain; middle forecast almost noneSat 9 p.m.–3 a.m.: 3 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.: 2 in 10 forecasts with measurable rain; middle forecast almost noneSun 3–9 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 9 p.m.–3 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 3–9 a.m.: 3 in 10 forecasts with measurable rain; middle forecast almost noneMon 9 a.m.–3 p.m.: 5 in 10 forecasts with measurable rain; middle forecast 0.3 mmMon 3–9 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.5 mmMon 9 p.m.–3 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 1.7 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)9 in 10<1 in 102.1 mm · <1 in 1045 km/h12°C–15°C
Wed 307 in 10<1 in 102.4 mm · <1 in 1025 km/h11°C–18°C
Thu 1nearly all9 in 1014 mm · 6 in 1046 km/h10°C–16°C
Fri 29 in 101 in 1018 mm · 8 in 1054 km/h9°C–12°C
Sat 39 in 10<1 in 1021 mm · 9 in 1035 km/h9°C–13°C
Sun 43 in 10<1 in 1022 mm · 9 in 1016 km/h8°C–15°C
Mon 56 in 103 in 1025 mm · 9 in 1036 km/h · 1 in 10 >64 km/h8°C–15°C
Tue 6 (part)7 in 105 in 1030 mm · 9 in 1036 km/h14°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 Sapporo

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