Why it matters: We're currently in the midst of "The Pollening" in Southeast Texas.
The big picture: The worst cities for allergies are concentrated in the South and the East Coast, the Asthma and Allergy Foundation of America says.
Threat level: Houston's tree pollen count alternated between heavy and extremely heavy over the last week, according to the Houston Health Department's daily counts.
Weed and grass pollen, along with mold spores, are fluctuating between low, medium and heavy, making predicting how bad the day will be for Houston's allergy sufferers difficult.
Pollen-related allergies are what many people call "hay fever."
Allergy symptoms vary by person, but they can include a runny nose, a stuffy nose, coughing, sneezing, watery eyes and nasal congestion.
Between the lines: Most major U.S. cities are suffering from longer allergy seasons amid human-caused climate change, according to new analysis from Climate Central.
"Climate change makes pollen seasons not only longer, but also more intense due to heat-trapping pollution," per Climate Central's report.
"Higher levels of planet-warming CO2 in the air can boost pollen production in plants, particularly in grasses and ragweed."
