Weather science (11)
I believe the answer is:
meteorology
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">weather science</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for meteorology that I've seen before include "Weather science" , "Weather forecasting" , "Study of weather and climate" .)