The winter season may start from October to November and last to May and April. In this period climbing to Damavand summit is very tough and dangerous. Because of high wind speed and very low temperature, stormy weather conditions, too much snowfall, icy trails and other risks, winter ascend is graded as very difficult. The ski and snowboard season is from December to mid-May, the best ski months are March & April.
Weather condition in mount Damavand is harsh and severe in winter time. Since the end of October we expect snow fall in high altitudes, which means the condition is considered like winter. The temperature stays sub-zero till next June far up in Damavand.
The south route of Damavand is the easiest route to access during winter. This route is not technically difficult, but still challenging in extreme conditions of very high altitude. Indeed, those people who have previous experience of winter mountaineering and are physically fit have more chance to reach to the summit, while the stable weather condition is an important factor, too.
Damavand Weather could change to disastrous in winter, with strong winds more than 100km/h and freezing temperature below -70°C (-94 Fahrenheit). You must be well-experienced for such a difficult climb or ski mountaineering expeditions in harsh climate. Furthermore remember that rescue and medical facilities are not available in case of injury and emergency, so extra care should be taken for winter climbing and ski touring and it is done by your own risk.
The weather has caused more deaths than any other factor besides bad judgment by climbers. Some climbers appear to rely on weather forecast reports or none at all, but one should note they are forecasts too, and one day their forecast will probably be wrong.
In 1970 when Reinhold Messner attempted a winter climb to Mt Damavand Iran, due to adverse weather conditions failed, because he realized that despite a lack of technical difficulties, is not an easy mountain climbing, but a large and highly conditional alpine challenge.