It has been a year since the climate pattern known as La Nina ended, the longest period of so-called "neutral" conditions since 2004. And there is no sign of the phenomenon, or its counterpart El Nino, through summer, climate forecasters say.

La Nina, known for bringing mild winters to the mid-Atlantic, was last active from August 2011 through April 2012. The phenomenon is marked by warmer-than-average Pacific Ocean surface temperatures around the equator.

But since May of last year, those water temperatures have been in "neutral" territory, too cool for a La Nina but not cold enough for El Nino. There were signs of a developing El Nino around the middle of 2012, but it didn't happen. El Nino is known best in the Baltimore area for bringing snowy winters.

The stretch of at least 12 months of neutral conditions is the longest such span since one lasting from February 2003 to July 2004, according to U.S. climate data.

An El Nino/La Nina forecast climate researchers released Monday suggests neutral conditions will continue at least through summer.

Whether either phenomenon develops is most relevant when it comes to winter weather, though, according to the National Oceanic and Atmospheric Administration. That is when the patterns' influences are most apparent at continental U.S. latitudes.

Aside from bringing either mild (La Nina) or snowy (El Nino) conditions in Maryland, they are known for bringing alternating wet, dry, cold or warm conditions to different parts of the U.S., according to NOAA.