The only place that can provide accurate traffic for searched keywords would be on Adwords or Bing Ads - they contain first hand information on the number of searches performed for the specific keywords that they gather from their search engine.
So if you are targeting Google, then Adwords should provide a good glimpse on what to expect. Or if you have some money to spend, you can even use Adwords to test an ad on their search engine and that should provide you with an even better daily overview.