How Accurate is the Weather Forecast in Japan?
Japan Meteorological Agency publishes the result of their weather forecasts. It is the percentage of right forecasting cases.
The below is the average percentage of the right forecasts which predicted a chance of rain (data in 1992 - 2013). If a forecast says that there is a chance of rain, we will have rain with a probability of 83%.
Table : Percentage of right forecasting cases by region (%)
Annual average | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa |
Nationwide Average |
Tomorrow's forecast | 78 | 84 | 85 | 84 | 84 | 78 | 83 |
2 days after | 74 | 80 | 81 | 80 | 81 | 75 | 79 |
3 days after | 70 | 75 | 76 | 75 | 75 | 71 | 74 |
4 days after | 67 | 73 | 73 | 73 | 73 | 69 | 71 |
5 days after | 66 | 71 | 71 | 70 | 71 | 67 | 69 |
6 days after | 64 | 70 | 69 | 69 | 69 | 66 | 68 |
7 days after | 62 | 69 | 68 | 67 | 68 | 65 | 66 |
3 - 7 days after, average | 66 | 72 | 72 | 71 | 71 | 67 | 70 |
January | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 71 | 90 | 85 | 83 | 81 | 78 | 82 |
2 days after | 68 | 87 | 83 | 80 | 77 | 75 | 80 |
3 days after | 68 | 84 | 81 | 80 | 75 | 69 | 77 |
4 days after | 66 | 83 | 79 | 76 | 72 | 68 | 75 |
5 days after | 64 | 80 | 76 | 73 | 70 | 66 | 73 |
6 days after | 64 | 80 | 75 | 72 | 68 | 64 | 71 |
7 days after | 63 | 79 | 74 | 70 | 68 | 62 | 70 |
3 - 7 days after, average | 65 | 81 | 77 | 74 | 71 | 66 | 73 |
February | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 73 | 88 | 86 | 84 | 84 | 80 | 83 |
2 days after | 70 | 85 | 82 | 81 | 82 | 78 | 80 |
3 days after | 66 | 81 | 79 | 77 | 77 | 73 | 76 |
4 days after | 65 | 79 | 77 | 73 | 74 | 70 | 73 |
5 days after | 64 | 79 | 75 | 71 | 71 | 68 | 72 |
6 days after | 63 | 77 | 74 | 70 | 69 | 66 | 70 |
7 days after | 62 | 76 | 72 | 68 | 68 | 64 | 68 |
3 - 7 days after, average | 64 | 78 | 75 | 72 | 72 | 68 | 72 |
March | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 75 | 86 | 86 | 84 | 86 | 81 | 83 |
2 days after | 71 | 81 | 83 | 81 | 83 | 78 | 79 |
3 days after | 67 | 77 | 79 | 77 | 79 | 72 | 75 |
4 days after | 66 | 75 | 76 | 74 | 73 | 70 | 72 |
5 days after | 64 | 72 | 71 | 69 | 70 | 68 | 69 |
6 days after | 63 | 71 | 69 | 69 | 69 | 66 | 67 |
7 days after | 61 | 68 | 67 | 64 | 68 | 64 | 65 |
3 - 7 days after average | 64 | 73 | 73 | 70 | 72 | 68 | 69 |
April | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 79 | 85 | 88 | 87 | 88 | 78 | 85 |
2 days after | 76 | 83 | 84 | 83 | 84 | 74 | 81 |
3 days after | 71 | 76 | 78 | 76 | 79 | 71 | 75 |
4 days after | 69 | 74 | 74 | 74 | 75 | 67 | 72 |
5 days after | 67 | 72 | 73 | 73 | 73 | 67 | 71 |
6 days after | 65 | 69 | 69 | 70 | 70 | 66 | 68 |
7 days after | 63 | 67 | 66 | 67 | 67 | 65 | 65 |
3 - 7 days after, average | 67 | 72 | 72 | 72 | 73 | 67 | 70 |
May | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 82 | 85 | 87 | 87 | 88 | 79 | 85 |
2 days after | 78 | 80 | 83 | 83 | 84 | 75 | 81 |
3 days after | 72 | 75 | 78 | 77 | 78 | 69 | 76 |
4 days after | 70 | 72 | 74 | 73 | 75 | 66 | 72 |
5 days after | 68 | 69 | 72 | 72 | 74 | 65 | 70 |
6 days after | 66 | 66 | 69 | 70 | 71 | 61 | 68 |
7 days after | 65 | 65 | 68 | 69 | 70 | 60 | 66 |
3 - 7 days after, average | 68 | 69 | 72 | 72 | 74 | 64 | 71 |
June | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 83 | 79 | 82 | 83 | 83 | 79 | 82 |
2 days after | 79 | 72 | 77 | 77 | 76 | 75 | 76 |
3 days after | 73 | 66 | 68 | 68 | 69 | 73 | 69 |
4 days after | 71 | 62 | 66 | 66 | 66 | 71 | 66 |
5 days after | 70 | 59 | 61 | 60 | 61 | 71 | 63 |
6 days after | 68 | 56 | 59 | 59 | 60 | 72 | 61 |
7 days after | 67 | 56 | 55 | 55 | 58 | 72 | 59 |
3 - 7 days after, average | 70 | 60 | 62 | 61 | 63 | 72 | 64 |
July | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 80 | 77 | 80 | 80 | 81 | 78 | 79 |
2 days after | 75 | 72 | 76 | 76 | 77 | 74 | 75 |
3 days after | 68 | 65 | 68 | 69 | 69 | 72 | 68 |
4 days after | 65 | 63 | 65 | 68 | 68 | 70 | 66 |
5 days after | 65 | 61 | 64 | 68 | 67 | 69 | 65 |
6 days after | 63 | 61 | 65 | 68 | 66 | 68 | 64 |
7 days after | 63 | 61 | 63 | 67 | 66 | 67 | 64 |
3 - 7 days after, average | 65 | 62 | 65 | 68 | 67 | 69 | 66 |
August | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 80 | 78 | 79 | 80 | 79 | 74 | 79 |
2 days after | 76 | 74 | 76 | 76 | 74 | 70 | 75 |
3 days after | 69 | 68 | 70 | 71 | 68 | 66 | 69 |
4 days after | 67 | 67 | 68 | 69 | 66 | 65 | 67 |
5 days after | 65 | 65 | 67 | 68 | 66 | 65 | 65 |
6 days after | 63 | 65 | 66 | 67 | 64 | 64 | 64 |
7 days after | 62 | 64 | 65 | 66 | 62 | 63 | 63 |
3 - 7 days after, average | 65 | 66 | 67 | 68 | 65 | 65 | 66 |
September | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 81 | 82 | 83 | 82 | 84 | 76 | 81 |
2 days after | 76 | 78 | 79 | 77 | 80 | 73 | 77 |
3 days after | 70 | 70 | 71 | 71 | 75 | 68 | 71 |
4 days after | 66 | 66 | 68 | 68 | 73 | 65 | 67 |
5 days after | 63 | 65 | 65 | 67 | 71 | 64 | 66 |
6 days after | 62 | 63 | 64 | 66 | 71 | 64 | 64 |
7 days after | 60 | 61 | 62 | 65 | 71 | 64 | 63 |
3 - 7 days after, average | 64 | 65 | 66 | 67 | 72 | 65 | 66 |
October | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 80 | 85 | 87 | 87 | 87 | 77 | 84 |
2 days after | 77 | 80 | 83 | 83 | 84 | 74 | 81 |
3 days after | 71 | 77 | 78 | 78 | 82 | 70 | 76 |
4 days after | 69 | 75 | 76 | 77 | 81 | 69 | 74 |
5 days after | 65 | 73 | 75 | 74 | 78 | 68 | 72 |
6 days after | 63 | 72 | 74 | 73 | 78 | 68 | 71 |
7 days after | 60 | 71 | 72 | 71 | 76 | 67 | 69 |
3 - 7 days after, average | 66 | 73 | 75 | 75 | 79 | 68 | 72 |
November | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 78 | 88 | 88 | 86 | 86 | 80 | 84 |
2 days after | 74 | 84 | 85 | 83 | 85 | 75 | 81 |
3 days after | 71 | 81 | 81 | 79 | 78 | 71 | 77 |
4 days after | 70 | 78 | 79 | 76 | 75 | 68 | 74 |
5 days after | 67 | 77 | 76 | 74 | 72 | 67 | 72 |
6 days after | 65 | 75 | 75 | 73 | 72 | 66 | 71 |
7 days after | 62 | 74 | 74 | 71 | 70 | 64 | 69 |
3 - 7 days after, average | 67 | 77 | 77 | 75 | 73 | 67 | 73 |
December | Sapporo | Tokyo | Nagoya | Osaka | Fukuoka | Okinawa | Average |
Tomorrow | 75 | 89 | 86 | 84 | 84 | 81 | 83 |
2 days after | 71 | 87 | 83 | 80 | 80 | 78 | 80 |
3 days after | 70 | 84 | 81 | 78 | 77 | 73 | 77 |
4 days after | 67 | 84 | 79 | 76 | 75 | 72 | 76 |
5 days after | 65 | 82 | 77 | 73 | 74 | 69 | 73 |
6 days after | 64 | 82 | 75 | 72 | 73 | 68 | 73 |
7 days after | 62 | 82 | 76 | 72 | 74 | 66 | 72 |
3 - 7 days after, average | 65 | 83 | 78 | 74 | 74 | 69 | 74 |
Source is Japan Meteorological Agency. 降水の有無の適中率の例年値
www.data.jma.go.jp/fcd/yoho/kensho/reinen.html
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