I want to ask about the local weather from January to June and what kind of clothes I should bring when I go to San Francisco to learn ESL next year. Thank you.

There is no way to say this now, because the weather can only be said for the short term within 15 days, and the weather for more than 1 month should be the climate.

San Francisco has a Mediterranean climate. Since there are The towering Rocky Mountains prevent the cold air from North America from reaching this place. Therefore, the winter here is warm, and the humid westerly wind affects more rainfall. If you choose a place in China based on temperature alone, it should be similar to Xiamen. You can Please refer to the clothes you bring when going to Xiamen in winter. In summer, there is little rainfall due to the influence of the subtropical high pressure, but the cold current along the coast makes the temperature not very high. In June, you can refer to the summer clothing in the coastal areas of the Shandong Peninsula.