月ごとの値
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室蘭（胆振地方) 2018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 | ||||||||||||||
| -1.2 | 1.1 | 7.6 | 09 | -4.7 | 29 | -3.4 | -10.1 | 25 | 3.6 | 01 | 20 | 0 | 27 | 0 | 11 | 0 | 0 | 0 | 4.2 | 72 | 45 | 22 | |
| -2.6 | 0.0 | 4.0 | 23 | -6.3 | 12 | -4.8 | -8.8 | 12 | -0.7 | 10 | 25 | 0 | 28 | 0 | 11 | 0 | 0 | 0 | 3.7 | 72 | 43 | 20 | |
| 3.0 | 6.4 | 16.7 | 28 | -0.8 | 06 | -0.4 | -6.1 | 06 | 4.5 | 25 | 5 | 0 | 16 | 0 | 2 | 0 | 0 | 0 | 5.6 | 71 | 23 | 29 | |
| 7.2 | 11.5 | 22.6 | 30 | 3.2 | 06 | 3.9 | 0.3 | 04 | 11.6 | 30 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7.5 | 73 | 24 | 27 | |
| 11.4 | 15.9 | 23.3 | 21 | 7.9 | 06 | 8.2 | 5.1 | 09 | 11.4 | 31 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 10.6 | 79 | 28 | 22 | |
| 14.7 | 18.5 | 24.8 | 30* | 11.3 | 13 | 11.6 | 7.2 | 15 | 17.5 | 30 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 14.4 ) | 86 ) | 45 ) | 04 | |
| 18.9 | 22.1 | 28.0 | 21 | 13.2 | 07 | 16.8 | 11.6 | 07 | 20.6 | 31 | 0 | 0 | 0 | 0 | 0 | 8 | 0 | 0 | 20.7 | 94 | 49 | 11 | |
| 20.1 | 23.2 | 29.6 | 01 | 18.1 | 05 | 18.0 | 12.9 | 17 | 21.9 | 23 | 0 | 0 | 0 | 0 | 0 | 8 | 0 | 0 | 20.7 | 88 | 47 | 02 | |
| 18.5 | 21.7 | 26.5 | 06* | 16.2 | 10 | 15.7 | 11.6 | 11 | 19.8 | 05 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 17.4 | 82 | 40 | 19 | |
| 13.9 | 17.3 | 22.4 | 01 | 11.4 | 31* | 10.7 | 5.9 | 19 | 15.7 | 01 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 12.5 | 78 | 41 | 04 | |
| 7.9 | 10.7 | 16.7 | 04 | 2.1 | 23 | 5.4 | -2.4 | 30 | 12.2 | 09 | 1 | 0 | 3 | 0 | 0 | 0 | 0 | 0 | 7.8 | 70 | 39 | 28 | |
| 0.6 | 2.7 | 13.1 | 04 | -4.4 | 27 | -1.6 | -7.4 | 27 | 8.9 | 04 | 17 | 0 | 23 | 0 | 8 | 0 | 0 | 0 | 4.8 | 73 | 44 | 19 | |