月ごとの値
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室蘭（胆振地方) 1987年（月ごとの値） 詳細（気温・蒸気圧・湿度）
| 月 | 気温(℃) | 蒸気圧 (hPa) | 湿度(％) | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 日平均 | 最高気温 | 最低気温 | 各階級の日数（平均） | 各階級の日数（最低） | 各階級の日数（最高） | ||||||||||||||||||
| 平均 | 平均 | 最高 | 最低 | 平均 | 最低 | 最高 | ＜0℃ | ≧25℃ | ＜0℃ | ≧25℃ | ＜0℃ | ≧25℃ | ≧30℃ | ≧35℃ | 平均 | 平均 | 最小 | ||||||
| 値 | 日 | 値 | 日 | 値 | 日 | 値 | 日 | 値 | 日 | ||||||||||||||
| -3.1 | -0.9 | 5.6 | 17 | -5.3 | 20 | -5.4 | -8.4 | 11 | -0.2 | 29 | 25 | 0 | 31 | 0 | 21 | 0 | 0 | 0 | 3.6 | 70 | 39 | 25 | |
| -2.6 | -0.4 | 5.4 | 10 | -7.0 | 15 | -4.6 | -9.4 | 15 | 1.7 | 11 | 21 | 0 | 26 | 0 | 15 | 0 | 0 | 0 | 3.5 | 67 | 28 | 03 | |
| 0.3 | 2.9 | 9.3 | 29 | -2.9 | 06 | -1.7 | -6.2 | 06 | 2.6 | 29 | 14 | 0 | 25 | 0 | 3 | 0 | 0 | 0 | 4.6 | 71 | 37 | 16 | |
| 5.1 | 9.1 | 19.0 | 30 | 1.9 | 12 | 1.6 | -2.4 | 01 | 4.1 | 28* | 1 | 0 | 3 | 0 | 0 | 0 | 0 | 0 | 6.1 | 70 | 24 | 16 | |
| 10.7 | 15.6 | 23.5 | 09 | 8.8 | 24 | 6.8 | 2.5 | 07 | 11.5 | 01 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 9.4 | 74 | 19 | 09 | |
| 15.7 | 19.6 | 26.9 | 26 | 12.9 | 12 | 12.7 | 10.1 | 01 | 16.7 | 24 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 0 | 14.6 | 83 | 28 | 01 | |
| 18.8 | 22.1 | 28.1 | 28 | 15.5 | 06 | 16.6 | 13.7 | 01 | 20.2 | 25 | 0 | 0 | 0 | 0 | 0 | 8 | 0 | 0 | 18.9 | 87 | 42 | 03 | |
| 19.1 | 21.3 | 25.6 | 14 | 16.7 | 02* | 17.6 | 14.2 | 02 | 19.6 | 31 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 0 | 20.0 | 91 | 62 | 15 | |
| 18.1 | 21.1 | 24.3 | 01 | 17.2 | 17 | 15.6 | 10.7 | 29 | 20.2 | 08* | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 16.4 | 77 | 37 | 29 | |
| 12.9 | 16.0 | 23.2 | 05 | 8.2 | 21 | 9.6 | 4.4 | 31 | 15.4 | 07 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 10.6 | 67 | 35 | 28 | |
| 4.8 | 7.9 | 15.2 | 12 | -4.0 | 28 | 2.0 | -6.4 | 28 | 8.8 | 03 | 5 | 0 | 10 | 0 | 3 | 0 | 0 | 0 | 6.2 | 67 | 36 | 11 | |
| -0.4 | 2.2 | 8.8 | 27 | -4.2 | 31 | -3.0 | -10.2 | 31 | 4.0 | 27 | 18 | 0 | 25 | 0 | 10 | 0 | 0 | 0 | 4.3 | 68 | 39 | 29 | |