How hot is it in the U.S.? Birds are using pot holders to pull worms out of the ground. Cows are giving evaporated milk. Trees are fighting over dogs. I'll mercifully spare you from more corny jokes about the high August temperatures, but you get the picture.

While the heat is on outside, though, the stock market hasn't been so hot lately. However, even with the broader indexes languishing, not all stocks are suffering. Investors seeking good opportunities need to look no further than the biotech industry -- especially small biotech stocks, which can benefit from catalysts that allow them to soar even when markets are struggling.

Which small biotechs stand out from the crowd? Celldex Therapeutics (NASDAQ:CLDX) looks attractive with its brain cancer vaccine Rintega. Potential approval for its hepatitis-B vaccine could make Dynavax Technologies (NASDAQ:DVAX) a big winner. Idera Pharmaceuticals (NASDAQ:IDRA) could have good news on the horizon from clinical trials. Ligand Pharmaceuticals (NASDAQ:LGND) claims multiple partnerships that might translate to huge success. And Portola Pharmaceuticals (NASDAQ:PTLA) could have at least one potential blockbuster drug in its pipeline.

Watch the slideshow below to find out why these five small biotech stocks could soon get hotter than the August heat.