According to the Koppen climatic classification, the letter code Cfa denotes

According to the Köppen climatic classification, the letter code 'Cfa' denotes the Humid Subtropical climate, also known as the Warm Temperate Eastern Margin or China Type climate [2][4]. The code is derived from three components: 'C' represents warm temperate (mesothermal) climates where the coldest month's average temperature is between -3°C and 18°C; 'f' indicates no distinct dry season with precipitation occurring year-round; and 'a' signifies a hot summer with the warmest month exceeding 22°C [4]. These regions are typically found on the eastern margins of continents between 20° and 35° latitudes [4]. In contrast, 'Af' represents tropical wet climates [1], 'Aw' denotes tropical wet and dry (savanna) climates [2], and 'ET' refers to the tundra climate [2][5].

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 30: Climatic Regions > Economy > p. 451
2. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 30: Climatic Regions > 30.2. A – Tropical Humid Climates > p. 423
3. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 30: Climatic Regions > Köppen–Geiger Climate Classification > p. 422
4. [5] https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification