Summer is full of local environmental stories. The TipSheet reminds environmental journalists that deep in the vault of SEJ's website, there are some great resources for covering them.
WILDFIRE is a local environmental story in many parts of the country at this time of year. Huge conflagrations hit drought-stricken Texas and Arizona earlier this year. Despite a temporary lull in major fires, underlying conditions remain bad in many places and the 2011 fire season so far has already charred more acres than the average year. See the TipSheet of June 22, 2011.  Another good place to start is the Journalist's Toolbox on Wildfire  in SEJ's Web Library.
EXTREME HEAT is currently hammering much of North America, and it is a story not only as a lethal hazard to vulnerable populations, but as a problem for farms and ranches and a pressure-cooker for air pollution. See the TipSheet of July 7, 2010. 
HURRICANE season is just getting under way as ocean temperature rises, preparing to peak in August and September. While the US has been largely unscathed so far, there is a significant probability of a major hurricane landfall — and major news. Being prepared is a good by-word for journalists as well as homeowners. Start with the Journalist's Toolbox on Hurricanes  in SEJ's Web Library.
RECREATION is on everyone's mind during vacation season. Chances are there is a beach, campground, refuge, or National Park not far from you and your audience. You can find out about beach water quality from NRDC  or EPA.  What's up at your local unit of the National Wildlife Refuge System  or National Park System. 
There's lots more: drought,  electric brownouts,  UV rays and sunscreen,  insect-borne disease like West Nile virus,  fishing,  dead zones,  and algal blooms.  For more ideas, check out some of the TipSheet's old summer re-runs.  Even though some sources are out-of-date, you can start with them as springboards for more up-to-date information.