Isohyets 




http://www.hko.gov.hk/wxinfo/pastwx/mws201206.htm

Isohyets are maps that show lines of equal value.  Although these maps can relate to isotachs and isobars, isohyets give information on rainfall in a given period.  In the map provided there are lines which are connected according to equal value for rain fall.  The map shows distinct barriers where lines don't meet and colors change.  As the map changes so does the amount of rainfall.  The dark red and yellows represent higher rainfall than the blues and greens.