Even small concentrations of smoke pollution from wildfires can be harmful to human health.
The number of days a year that mosquitoes can transmit disease is increasing in much of the U.S.
The number of consecutive hot summer days, or heat streaks, is increasing in much of the U.S.
The number of extremely hot summer days is increasing in much of the U.S., and with it, the risk of heat-related illness.
The 30-year average temperature, known as the meteorological normal, is rising in most locations in the U.S.
The number of days with heavy precipitation is increasing in most locations in the U.S.
Western spring snowpack has been below normal six of the past seven years, meaning less water during the traditionally dry summer months.
Before the end of this century, the cherry blossoms in Washington, D.C. may bloom a month earlier on average than they do today.