Assistant API results are not so good. What do i do wrong?

I have created the AI assistant using the assistant api.
I use the model gpt-3.5-turbo-1106 + file search.
I am attaching 3 text files with information to the assistant (total 500kb).
The format of files is markdown (but i also tried with json and txt)

One of files has weather information for places (as a table). The first column is a place name and then the forecast.
Instructions describes how to use the file.

I am asking the agent to get me weather information in some place. Often the first response is “i do not have information about the weather”. If i write “are you sure?” then API can return good response with the info from that file.
But sometimes i have to ask third time “hey, you have the file. Get info from it”. And it finally responds.

Of course my users do not want to ask the second/third time.

How to solve this problem? How to force the API to use the attached file as the top priority for every new thread?

Also, i am updating attached files every 3 hours (because weather is changed). I remove previous files and upload new to the agent. Maybe this affects on how the API works?