Bad weather will make Giro d'Italia's first mountain stage a tough test

Up until this morning, the 2016 Giro d'Italia has been blessed with fine weather, both during its start in the Netherlands and when the race returned to Italy on Tuesday.

All that has now changed. As the riders arrive at Ponte this morning for stage six they will face not only the first mountain stage of the 2016 Giro, but also torrential rain and fog.

>>> Giro d'Italia 2016: Latest news, reports and info

Dark clouds are shrouding the Apennine mountain range, where the 157km stage will finish with an ascent to Roccarsco.

The day is billed to be one for the climbers and general classification contenders to show their hand - as well as appointing a new leader in the King of the Mountains competition.

Current race leader Tom Dumoulin (Giant-Alpecin) will face a challenge to keep hold of the pink jersey. Dumoulin has said that he has not specifically trained at altitude prior to the race. Despite this, he placed second on hilly stage four to retake the GC lead from sprinter Marcel Kittel (Etixx-QuickStep).

The final ramp to Roccaraso is not particularly steep, but it is a drag: it could well suit Dumoulin, whose ability to produce a steady power output over a set distance has established him as one of the world's best time triallists.

However, one rider has a proven track record in excelling in bad conditions at the Giro: Vincenzo Nibali (Astana). The 2013 winner is likely to be in the thick of the action in the finale – though we could also see the GC favourites take a measured approach and finish as a group, mindful of the weeks to come.

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Prior to the final climb, the riders must tackle the Bocca della Selva in the first half of the stage. It's another steady ascent over 18km, but it might be the subsequent descent that will jangle nerves on wet roads.