Check the weather forecast using Accuweather.com as reference dude
The annual averages on https://www.holiday-weather.com/ may give a better idea of what to expect. Although it is the rainy season it will not necessarily rain every day and it would be rare to rain all day.
Weather forecasts can also be deceptive until you can drill down into hourly forecasts. Looking at a rainy day you will often see a couple hours with a 90% probability of rain while most of the time it could be 20%. This also matches what actually tends to happen: a downpour for an hour or some hours and the rest of the day mostly cloudy but without rain.
The forecasts are also misleading because they are for Bangkok as if it were a single point while in fact the city covers over 1,500 square kilometers. The reality is that attractions in suburbs might be under a downpour while downtown is dry (or vice versa).
The biggest issue is that with 7 days in Phuket it is quite possible to have a spell of high winds and rough seas that make boat tours and swimming in the sea too dangerous during your stay. It is not an issue in Pattaya which has no wonderful marine tours and where swimming is best done in a pool due to pollution.Edited: 05 August 2018, 07:15