GB/T 33675-2026Grades of cold winter (English PDF)

4.1 Single-station cold winter

4.1.1 The cold winter of a single station should be determined based on the average winter temperature anomaly of the effective stations and the cold winter threshold of a single station.

4.1.2 The average winter temperature anomaly and the single-station cold winter threshold are determined according to A.3 and A.5 of Appendix A, respectively.

4.1.3 When the average winter temperature anomaly of a valid station is less than or equal to the single-station cold winter threshold, the winter of that station is determined to be a single-station cold winter.

4.2 Regional cold winters

4.2.1 Regional cold winters should be determined based on the regional cold winter index and the regional cold winter threshold.

4.2.2 The regional cold winter index is determined according to B.6 of Appendix B, and the regional cold winter threshold is 50%.

4.2.3 When the cold winter index of a certain region is greater than or equal to 50%, the winter of that region is determined to be a cold winter.

4.3 Nationwide Cold Winter

4.3.1 The national cold winter should be determined based on the national cold winter index and the national cold winter threshold.

4.3.2 The national cold winter index is determined according to C.3 in Appendix C, and the national cold winter threshold is 50%.

4.3.3 When the national cold winter index is greater than or equal to 50%, the winter is determined to be a national cold winter.

5.1 Single-station cold winter level

5.1.1 Once a single station is determined to be experiencing a cold winter, the cold winter level of the single station should be classified according to the single station cold winter level index and the single station cold winter threshold.

5.1.2 The single-station cold winter level index is the winter average temperature anomaly, calculated according to A.3, and the single-station cold winter threshold value is determined according to A.5.

5.1.3 Single-station cold winter levels are divided into single-station weak cold winter and single-station strong cold winter. When the average winter temperature anomaly of a valid station is less than or equal to... When the temperature at a station is -

0.34 times the standard deviation of the temperature but greater than -

1.29 times the standard deviation of the temperature, it is classified as a single-station weak cold winter; when the winter average temperature at a certain valid station is... When the average temperature anomaly is less than or equal to -

1.29 times the standard deviation of temperature, it is classified as a single-station severe cold winter. The classification of single-station cold winters is as specified in Table 1.

5.2 Regional Cold Winter Level

5.2.1 Once a region is determined to be a cold winter, the regional cold winter level should be classified according to the regional cold winter level index and the regional cold winter threshold.

5.2.2 The regional cold winter level index is determined based on the regional cold winter index and the regional severe cold winter index. The regional cold winter index is determined as B.6. The severe cold winter index is determined by B.8.The threshold for a regional weak cold winter is 50%, and the threshold for a regional severe cold winter is 25%.

5.2.3 Regional cold winters are classified into two levels. weak regional cold winters and strong regional cold winters. A regional cold winter index greater than or equal to 50% and a strong regional cold winter index... If the regional cold winter index is less than 25%, it is classified as a weak cold winter; if the regional cold winter index is greater than or equal to 50% and the regional strong cold winter index is greater than or equal to... 25% is classified as a region with a severe cold winter. The regional cold winter levels are classified according to the provisions of Table 2.

5.3 National Cold Winter Levels

5.3.1 Once a cold winter is determined nationwide, the national cold winter level should be classified according to the national cold winter level index and the national cold winter threshold.

5.3.2 The national cold winter level index is determined based on the national cold winter index and the national severe cold winter index. The national cold winter index is determined as C.3. The severe cold winter index is determined by C.5.The national threshold for a weak cold winter is 50%, and the national threshold for a severe cold winter is 25%.

5.3.3 National cold winters are classified into two levels. a weak cold winter and a strong cold winter. A national cold winter index greater than or equal to 50% and a strong cold winter index... A winter index of less than 25% is classified as a weak cold winter nationwide; a winter index of 50% or higher and a strong cold winter index of 50% or higher are classified as strong cold winters nationwide. 25% is classified as a severe cold winter nationwide. The national cold winter classification is based on the provisions of Table 3.