Autumn (early Oct to early Dec), is the peak season: generally dry, stable and very clear, although there can be the odd shower or freak autumn storm. It gets progressively colder at night higher up, but the chill is rarely severe until December and daytime temperatures are pleasantly cool for walking; at low elevations it can be distinctly hot. The fine conditions mean that the main Annapurna and Everest trails will be busy: porters will charge top dollar, flights will be tight, and guides will race ahead to book up lodges – forcing some independent trekkers to carry on up the trail to the next village to find a bed. The other drawback is the general lack of greenery on the freshly ploughed terraces in the Middle Hills. In general, autumn is a good time to think about getting off the beaten track.
After winter, temperatures and the snow line rise steadily during spring (Feb–April). The warmer weather also brings more trekkers, though not nearly as many as in autumn. The main factor that keeps the numbers down is a disappointing haze that creeps up in elevation during this period, plus the occasional sudden downpour (or freak snowstorm) and sometimes unpleasant afternoon winds. By April, you probably won’t get good views until you reach 4000m or so, though this is also the time when the most colourful rhododendrons bloom, generally between 2000m and 3000m.