*** Tuesday’s Forecast: Dew point temperatures will rise through the overnight hours into Tuesday with a south/southwesterly breeze develops by the afternoon as another warm and humid day is in store for early August. Early sunshine, with some patchy morning fog possible, will give way to a mix of sun and clouds for the afternoon. Scattered showers and thunderstorms are possible with best chances occurring late in the afternoon hours. PM-2.5 concentrations will remain at levels inside the moderate range. Ozone concentrations will climb to the higher end of the moderate range with some areas reaching the Code Orange (Unhealthy for Sensitive Groups) range. Increasing cloud cover due to the scattered late afternoon showers will be what helps those areas that see concentrations limited to the high moderate range. Highs will be in the upper 80s for the day.An Air Quality Action Day will be in effect for Monday! Sunshine most of the time Monday with high temperatures in the lower 90s will allow for robust ozone development. Increased weekday mobile source emissions will allow for ozone concentrations to reach the code ORANGE range. Fine particulate levels will remain moderate with light west to southwest winds and elevated humidity.

 *** Extended Outlook: A cold front will begin to approach the region as early as Wednesday, bringing some drier and slightly cooler air to the area for late in the week. Temperatures will remain in the high-80s for highs Wednesday and Thursday before being in the low to mid-80s for Friday and at least Saturday. Chances for showers and thunderstorms Wednesday and Thursday will limit ozone formation, so concentrations will be limited to the high good to low moderate range. PM-2.5 concentrations may remain at moderate levels for Wednesday but will improve as we progress through the remainder of the week with the combination of a change in air mass and the scattered precipitation. 

Help prevent air pollution by:

  • Taking transit

  • Refueling your vehicle at night

  • Conserving energy in your home


To follow air quality in PHL between forecasts:


For more information, contact the Air Quality Partnership at 215-238-2860.