I just returned from Ecuador after a successful climb of both Cotopaxi and Chimborazo. We were however extremely lucky with the weather as the Andes were covered with loads of snow just the week before we arrived. Now the weather seems to have deteriorated again which makes all climbs very difficult.
During the period December 1-10 the conditions were great on both mountains (except for a collapsing snowbridge up at the great crevasse on Cotopaxi at 5.500m (which now can be passed to the left!)
On Chimbo’s Castillo route we hade excellent conditions. We made a tented camp up at El Castillo and had absolutely no problems with the snow covered flank all the way straight up to Cumbre Whymper. As the snow cover was massive no ice at all on the slopes. Although we obviously carried full glacier travel equipment I guess it would have been possible to climb this route only with ski poles and I would say that soloing would have worked out just fine. But of course this was due to exceptional good conditions and perfect weather at the time. The only objective danger we experienced was the descent through El Corridor as we got down just before noon when the snow became soft and rockfall was due.
Exactly as Scott says above; the conditions on Chimbo changes extremely quick so keep that in mind. On the three days we were in the area, it was more and less cloudless from midnight until 7-8am but then the clouds and fog came and by noon El Castillo and the Corridor route was in a thick whiteout. The use of a GPS came in handy as there were hundreds of different “false” tracks all over the slopes.
Good luck // André