Being an inner Himalayan valley, the Nanda Devi Basin has a distinctive micro-climate. Conditions are generally dry with low annual precipitation, but there is heavy monsoon rainfall from late June to early September. Prevailing mist and low cloud during the monsoon keeps the soil moist, hence the vegetation is lusher than is usual in the drier inner Himalayan valleys. From mid April to June temperatures are moderate to cool (19 °C maximum). The Valley of Flowers also has the micro-climate of an enclosed inner Himalayan valley, and is shielded from the full impact of the southwest summer monsoon by the Greater Himalaya range to its south. There is often dense fog and rain especially during the late summer monsoon. Both Basin and Valley are usually snow-bound for six to seven months between late October and late March, the snow accumulating deeper and at lower altitudes on the shadowed southern than on the northern side of the valleys.