月ごとの値
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室蘭（胆振地方) 2003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 | ||||||||||||||
| -2.1 | 0.2 | 5.4 | 13 | -4.4 | 15 | -4.4 | -9.7 | 15 | 0.9 | 09 | 26 | 0 | 30 | 0 | 16 | 0 | 0 | 0 | 3.7 | 69 | 33 | 15 | |
| -1.8 | 0.8 | 5.4 | 08 | -2.3 | 12 | -4.3 | -7.5 | 12 | 1.2 | 09 | 22 | 0 | 26 | 0 | 9 | 0 | 0 | 0 | 3.8 | 69 | 40 | 15 | |
| 0.8 | 4.1 | 12.6 | 25 | -1.5 | 10 | -1.7 | -7.1 | 10 | 2.8 | 24 | 12 | 0 | 25 | 0 | 1 | 0 | 0 | 0 | 4.6 | 69 | 29 | 16 | |
| 6.1 | 10.1 | 17.8 | 17 | 4.5 | 09 | 2.8 | -0.3 | 01 | 6.5 | 29 | 0 | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 7.2 | 77 | 19 | 22 | |
| 9.8 | 13.9 | 21.5 | 03 | 7.6 | 19 | 6.9 | 2.0 | 01 | 11.5 | 31 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 9.9 | 82 | 20 | 02 | |
| 13.9 | 17.1 | 24.4 | 21 | 12.3 | 26 | 11.5 | 8.1 | 10 | 16.0 | 19 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 14.0 | 88 | 35 | 06 | |
| 15.0 | 17.6 | 23.3 | 12 | 13.4 | 04 | 13.3 | 11.5 | 04* | 16.1 | 31 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 15.2 | 89 | 52 | 06 | |
| 18.9 | 21.5 | 27.2 | 22 | 17.0 | 17 | 17.1 | 15.0 | 01 | 18.9 | 09 | 0 | 0 | 0 | 0 | 0 | 5 | 0 | 0 | 19.6 | 90 | 51 | 30 | |
| 17.3 | 20.6 | 24.7 | 01 | 16.2 | 08 | 14.6 | 10.4 | 21 | 18.2 | 03 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 16.3 | 82 | 43 | 15 | |
| 12.3 | 15.6 | 19.0 | 01 | 10.6 | 24 | 9.1 | 5.0 | 24 | 13.2 | 22 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 10.7 | 74 | 42 | 20 | |
| 7.2 | 10.3 | 20.1 | 03 | 2.4 | 26 | 3.7 | -2.1 | 26 | 10.6 | 02 | 0 | 0 | 6 | 0 | 0 | 0 | 0 | 0 | 7.5 | 69 | 36 | 13 | |
| 1.9 | 4.4 | 9.1 | 01 | -2.1 | 09 | -0.6 | -5.2 | 30 | 4.4 | 02 | 8 | 0 | 18 | 0 | 1 | 0 | 0 | 0 | 5.0 | 70 | 42 | 03 | |