平年値（旬ごとの値）
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室蘭（胆振地方) 平年値（旬ごとの値）
| 要素 | 海面気圧 (hPa) | 降水量 (mm) | 平均気温 (℃) | 日最高気温 (℃) | 日最低気温 (℃) | 相対湿度 (%) | 平均風速 (m/s) | 日照時間 (時) | 全天日射量 (MJ/㎡) | 降雪の深さ合計 (cm) | 最深積雪 (cm) | 雲量 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 統計期間 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | 1991～ 2020 | |
| 資料年数 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | |
| 1月 | 上旬 | 1011.9 | 18.9 | -1.1 | 1.1 | -3.4 | 70 | 6.1 | 24.7 | 4.9 | 13 | 8 | 8.0 @ |
| 中旬 | 1014.8 | 14.9 | -2.0 | 0.2 | -4.2 | 70 | 5.5 | 27.7 | 5.6 | 16 | 13 | 7.9 @ | |
| 下旬 | 1013.4 | 19.8 | -2.1 | 0.3 | -4.4 | 71 | 5.5 | 35.9 | 6.5 | 19 | 16 | 7.8 @ | |
| 2月 | 上旬 | 1012.9 | 11.9 | -2.3 | 0.1 | -4.6 | 71 | 5.3 | 37.9 | 7.8 | 17 | 16 | 7.6 @ |
| 中旬 | 1013.7 | 17.0 | -1.6 | 0.9 | -4.0 | 72 | 5.5 | 42.2 | 9.1 | 17 | 18 | 7.6 @ | |
| 下旬 | 1015.8 | 15.5 | -0.7 | 2.1 | -3.2 | 72 | 4.9 | 43.8 | 11.1 | 12 | 18 | 6.9 @ | |
| 3月 | 上旬 | 1014.1 | 22.2 | -0.1 | 2.7 | -2.7 | 72 | 5.1 | 53.8 | 12.0 | 15 | 16 | 6.9 @ |
| 中旬 | 1013.4 | 12.2 | 1.4 | 4.6 | -1.2 | 73 | 4.9 | 56.8 | 13.5 | 8 | 9 | 6.8 @ | |
| 下旬 | 1013.3 | 15.5 | 2.8 | 6.3 | 0.0 | 72 | 4.7 | 73.6 | 15.7 | 5 | 5 | 6.3 @ | |
| 4月 | 上旬 | 1013.1 | 16.4 | 4.5 | 8.3 | 1.7 | 73 | 4.5 | 66.4 | 16.3 | 1 | 1 | 6.3 @ |
| 中旬 | 1012.8 | 25.4 | 5.9 | 9.9 | 2.8 | 75 | 4.4 | 65.3 | 16.9 | 2 | 2 | 6.4 @ | |
| 下旬 | 1012.2 | 28.1 | 7.8 | 12.0 | 4.6 | 75 | 4.3 | 67.3 | 17.8 | 1 | 1 | 6.4 @ | |
| 5月 | 上旬 | 1011.7 | 42.4 | 9.3 | 13.6 | 6.1 | 77 | 4.3 | 64.6 | 18.0 | --- | --- | 6.9 @ |
| 中旬 | 1011.4 | 33.7 | 10.5 | 14.6 | 7.4 | 80 | 4.2 | 63.1 | 17.9 | --- | --- | 7.1 @ | |
| 下旬 | 1010.8 | 32.2 | 12.1 | 16.3 | 9.2 | 83 | 3.9 | 67.1 | 18.5 | --- | --- | 7.2 @ | |
| 6月 | 上旬 | 1011.1 | 33.4 | 13.0 | 16.9 | 10.4 | 87 | 3.8 | 54.7 | 18.3 | --- | --- | 7.7 @ |
| 中旬 | 1009.4 | 41.6 | 14.4 | 17.9 | 12.0 | 88 | 3.7 | 49.7 | 17.5 | --- | --- | 8.0 @ | |
| 下旬 | 1008.4 | 34.0 | 15.9 | 19.4 | 13.4 | 88 | 3.6 | 51.4 | 17.8 | --- | --- | 7.8 @ | |
| 7月 | 上旬 | 1008.6 | 56.5 | 17.1 | 20.3 | 15.0 | 90 | 3.6 | 44.8 | 16.2 | --- | --- | 8.2 @ |
| 中旬 | 1008.7 | 43.9 | 18.4 | 21.7 | 16.3 | 90 | 3.5 | 43.9 | 16.1 | --- | --- | 8.3 @ | |
| 下旬 | 1009.6 | 58.8 | 19.8 | 22.8 | 17.8 | 91 | 3.6 | 44.5 | 15.0 | --- | --- | 8.5 @ | |
| 8月 | 上旬 | 1010.1 | 51.1 | 20.9 | 24.0 | 18.8 | 90 | 3.4 | 47.1 | 15.5 | --- | --- | 7.9 @ |
| 中旬 | 1010.2 | 70.2 | 20.5 | 23.3 | 18.7 | 90 | 3.5 | 40.8 | 13.9 | --- | --- | 8.4 @ | |
| 下旬 | 1010.9 | 66.0 | 20.5 | 23.5 | 18.4 | 88 | 3.6 | 57.0 | 14.8 | --- | --- | 7.5 @ | |
| 9月 | 上旬 | 1011.7 | 50.0 | 20.0 | 23.0 | 17.6 | 86 | 3.8 | 51.9 | 13.8 | --- | --- | 7.3 @ |
| 中旬 | 1013.4 | 52.4 | 18.5 | 21.7 | 15.8 | 82 | 3.8 | 54.6 | 13.4 | --- | --- | 6.9 @ | |
| 下旬 | 1015.5 | 54.2 | 16.7 | 20.0 | 13.7 | 79 | 4.1 | 60.0 | 13.2 | --- | --- | 6.3 @ | |
| 10月 | 上旬 | 1015.5 | 44.8 | 14.9 | 18.1 | 11.9 | 77 | 4.4 | 54.1 | 11.5 | --- | --- | 6.3 @ |
| 中旬 | 1016.3 | 31.2 | 12.8 | 16.1 | 9.5 | 74 | 4.6 | 58.3 | 10.9 | --- | --- | 5.8 @ | |
| 下旬 | 1016.4 | 25.9 | 11.1 | 14.1 | 8.1 | 73 | 5.0 | 52.9 | 8.8 | --- | --- | 6.5 @ | |
| 11月 | 上旬 | 1016.0 | 28.5 | 9.0 | 12.1 | 5.9 | 71 | 5.4 | 41.0 | 7.2 | 0 | 0 | 6.8 @ |
| 中旬 | 1016.0 | 29.7 | 6.2 | 9.1 | 3.3 | 71 | 5.5 | 32.7 | 6.0 | 1 | 1 | 7.5 @ | |
| 下旬 | 1016.6 | 25.1 | 4.1 | 6.8 | 1.3 | 70 | 5.8 | 29.0 | 5.3 | 4 | 2 | 7.6 @ | |
| 12月 | 上旬 | 1015.8 | 23.2 | 1.8 | 4.3 | -0.6 | 70 | 6.0 | 23.9 | 4.6 | 6 | 4 | 8.1 @ |
| 中旬 | 1014.5 | 20.4 | 0.2 | 2.5 | -2.1 | 70 | 6.2 | 22.2 | 4.5 | 9 | 5 | 8.2 @ | |
| 下旬 | 1012.9 | 22.2 | -0.4 | 2.0 | -2.7 | 71 | 6.1 | 25.0 | 4.5 | 12 | 6 | 8.2 @ | |
- 「@」の付いた値は、参考値です。平年差や平年比に利用できません。