The weather office on Wednesday forecast heavy rainfall for coastal Karnataka.The coastal Karnataka districts include Uttara Kannada, Udupi and Dakshina Kannada.The south-west monsoon continues to be weak over interior Karnataka.Bengaluru city will experience a generally cloud sky with rain in some areas on Wednesday, an official said. No rainfall was recorded on Tuesday.The maximum temperature on Wednesday is likely to be around 30 degrees Celsius while the minimum temperature would be around 20 degrees Celsius, the official added.On Tuesday, Bengaluru recorded a maximum temperature of 30 degrees Celsius while the minimum temperature was 21.4 degrees Celsius.