The　occurrence　of　adverse　weather　exacerbates　traffic　flow　conditions,　often　leading　to　severe　traffic　congestions.　Many　studies　have　been　conducted　based　on　field-collected　data　to　obtain　the　effects　of　weather　on　traffic　flow　characteristics.　However,　there　is　a　limitation　for　filed　data-based　studies,　in　that　weather　conditions　and　traffic　conditions　are　both　noncontrollable　and　nonrepeatable,　making　it　difficult　to　comprehensively　assess　the　influence　of　weather　conditions,　especially　the　rare　extreme　weather　conditions,　on　traffic　flow　characteristics.　This　paper　proposes　to　assess　these　effects　with　the　combination　of　driving　simulator　and　traffic　simulation.　A　driving　simulator　can　collect　driving　behavior　by　conducting　weather-related　driving　simulation　experiments,　while　a　microscopic　traffic　simulation　program　can　evaluate　the　changes　in　traffic　flow　characteristics　by　inputting　driving　behavior　parameters　coming　from　the　driving　simulator.　The　proposed　method　can　overcome　the　limitation　of　the　field　data-based　approach.　In　this　paper,　the　structure　of　the　assessment　platform　is　introduced　at　first.　Then　a　verification　experiment　is　conducted　to　measure　the　influences　of　adverse　weather　conditions　on　traffic　flow　characteristics.　The　verification　experiment　results　show　that　the　influences　of　adverse　weather　on　traffic　flow　characteristics　have　consistent　tendencies　with　outcomes　from　previous　research　and　demonstrate　that　the　method　is　practicable　for　the　analysis　of　the　influence　of　weather　on　traffic　flow　characteristics.　This　paper　provides　a　practical　way　to　analyze　the　influence　of　weather　on　traffic　flow　from　driving　behavior＇s　point　of　view.