Based on the search results, it is not clear which pollen is high in San Antonio today. However, the following information can be found:

• The Weather Channel provides a 3-day outlook for the worst pollen offenders, including tree pollen, grass pollen, and ragweed pollen. As of October 5th, none of these are high today.
• AccuWeather provides a tree pollen allergen forecast for San Antonio, but it does not indicate whether tree pollen is high today.
• Kleenex lists several types of pollen that can be found in San Antonio, including ash, birch, elm, pine, poplar, juniper, maple, and oak. However, it does not indicate which of these is high today.
• Stone Oak Allergy provides a local allergy report for San Antonio, which includes information on grass, mold, ragweed, and tree pollen. As of October 5th, ragweed pollen is high, but tree pollen is low.

Therefore, based on the available information, it appears that ragweed pollen is high in San Antonio today.