I thought this was kind of neat but I've been spending too much time watching my
bees and wondering what pollen they're bringing in:
Pollen Allergy Forecast
Scroll down to see Today's Predominant Pollens. Make sure you put your location in. You can click on the species and it gives a pretty detailed description and where it's found in the US.
They listed
Ash, Oak, and Birch but no Dandelion so I'm scratching my head a little over that.