３か月ごとの値
 |  |
 |  |
 |  |  |  |  |
 |  |  |  |  |  |
 |  |  |  |  |
八丈島（東京都) 1991年（３か月ごとの値） 詳細（日照・雪・その他）
| 月 | 日照時間(h) | 全天日射量 (MJ/㎡) | 雪(cm) | 雲量 | 大気現象 | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 合計 | 日照率 | 各階級の日数 | 降雪 | 各階級の日数（降雪） | 最深積雪 | 各階級の日数（最深積雪） | 平均 | 各階級の日数 | 雪日数 | 霧日数 | 雷日数 | ||||||||||||||||||
| 不照 | 日照率 ≧40% | 平均 | 合計 | 日合計の最大 | ≧3cm | ≧5cm | ≧10cm | ≧20cm | ≧50cm | ≧100cm | 値 | 日 | ≧0cm | ≧1cm | ≧5cm | ≧10cm | ≧20cm | ≧50cm | ≧100cm | ＜1.5 | ≧8.5 | ||||||||
| 値 | 日 | ||||||||||||||||||||||||||||
11～1 | 332.0 | 37 | 5 | 38 | 8.0 | 0 | 0 | 01/23* | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 6.4 | 6 | 21 | 1 | 0 | 10 | |
12～2 | 331.3 | 36 | 5 | 37 | 8.5 | 0 | 0 | 02/26* | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 6.5 | 4 | 21 | 2 | 0 | 13 | |
1～3 | 316.8 | 32 | 12 | 33 | 9.4 | 0 | 0 | 03/15* | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.1 | 3 | 32 | 3 | 3 | 10 | |
2～4 | 361.9 | 34 | 15 | 33 | 11.7 | 0 | 0 | 03/15* | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.2 | 4 | 39 | 2 | 8 | 5 | |
3～5 | 359.5 | 30 | 19 | 30 | 13.0 | 0 | 0 | 03/15 | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.6 | 4 | 45 | 1 | 12 | 6 | |
4～6 | 327.9 | 26 | 18 | 26 | 13.6 | -- | -- | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 8.1 | 2 | 53 | 0 | 15 | 11 | ||
5～7 | 310.9 | 24 | 15 | 26 | 14.1 | -- | -- | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 8.5 | 1 | 62 | 0 | 13 | 19 | ||
6～8 | 370.4 | 29 | 11 | 30 | 15.0 | -- | -- | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 8.3 | 0 | 64 | 0 | 9 | 17 | ||
7～9 | 397.8 | 33 | 6 | 35 | 15.0 | -- | -- | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 8.0 | 0 | 58 | 0 | 4 | 16 | ||
8～10 | 371.3 | 33 | 11 | 33 | 12.8 | -- | -- | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.8 | 0 | 53 | 0 | 1 | 11 | ||
9～11 | 319.3 | 31 | 10 | 32 | 10.1 | -- | -- | 0 | 0 | 0 | 0 | 0 | 0 | -- | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.6 | 0 | 45 | 0 | 1 | 10 | ||
10～12 | 324.3 | 33 | 11 | 35 | 8.3 | 0 | 0 | 12/30* | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 12/30 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 7.1 | 2 | 37 | 0 | 0 | 7 |