The seasonality chart is available for all areas with ascents. It shows ascents by month and should give an idea about the best season to climb in a specific area.
Example seasonality charts. Note that winter is blue, spring is green, summer is yellow and fall is red. For crags in the tropical zone the chart is blue only.
Arapiles (southern hemisphere)
Effectively this shows relative popularity of an area over months. Be aware that the information might be skewed by factors like holidays (e.g. Easter or school holidays) or events that occur at a climbing area (such as climbing festivals). There is a bias towards months with these events. Please also note that the best months to climb in an area may not be the most popular.