Hovmoller diagrams are great for displaying large amounts of data in a meaningful and understandable form. The image on the left graphical shows the El Nino signal in the equatorial Pacific (100 W to 140 E longitude) since 1986(click to enlarge). This is a Hovmoller plot of 5-day mean, 2 N to 2S Sea Surface Temperatures (SST) and SST anomalies in the tropical pacific from NOAA PMEL (more info)
As another example this second image summarizes the vertical profile of ozone over the South Pole as measured by ozone sondes during the year 2001. This Hovmoller plot was obtained from NOAA CMDL . It clearly shows two important features of the ozone hole. The first is that the ozone hole occurs during September and October and is not a year-long phenomenon. Secondly, the ozone hole is not like a hole through your pants but more like a 3-dimensional hole in a loaf of bread.