Feb 10, 2014

Who rewound the water cycle?

One Big Rain Day down ...

Four still to go (i.e. the long-term annual average is five).

This bar chart shows south Florida's
annual number of Big Rain Days from 1992 to present 

What is a Big Rain Day exactly?

It's any day in which all of south Florida averaged an inch or greater of rain. That may not sound like a lot at first glance, but to have an inch spread across the entire south peninsula means that everywhere got significantly wet, or a portion got very very wet. Or in technical terms, that's a lot of rain.

This calendar chart reports daily rainfall across south Florida from 1992 to present.  Orange dots indicate days when little to no rain fell across south Florida.  Light blue dots indicate days when greater than 0.2 inches fell across south Florida.  The big black dots indicate the Big Rain Days (i.e. when 1 inch or greater of rain fell across south Florida).  The difference between the wet and dry season are the blue and orange dots.  Blue dots are the norm during the wet season and orange dots during the dry season.  Big Rain Day (black drops) occur every month of the year.  They have a big influence on making wet seasons really wet and keeping dry seasons from dropping into deep drought.

As you can see from the calendar chart above, Big Rain Days fall during all times of year. They are most common in June and September, but also occur during the winter, too. In fact, it is the regional winter rain events that help keep deep spring drought at bay. One winter Big Rain Day can balance a good twenty or thirty consecutive days of pure sun. Case in point was our first Big Rain Day of 2014:

Just one day of rain rewound the dry season clock back to December levels.

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