Pollen Forecast for Castro Valley, California

The amount of pollen in the air for Thursday will be falling and will remain in the extremely low range. This change results in part from rising humidity and expected precipitation in the morning, afternoon and evening which tends to wash pollen out of the air.

Concentration of pollen grains in the air for Friday will be unchanged in the extremely low range. This is a result of stable temperatures. Only trace amounts of pollen are in the air at this time. The next higher pollen levels in the area will from the early tree pollen types.