You can do the Annapurna Circuit Trek any time of the year; however, if you are looking for perfect weather conditions for trekking in Annapurna. In that case, Autumn (September-November) and Spring (March-April) are the two best seasons for Annapurna Circuit Trek in Nepal.
Autumn is the peak season to trek the Annapurna Circuit. Since autumn arrives right after the monsoon, the sky is bright and clear, the valleys are still green, the Annapurna Circuit weather and temperature are perfect for trekking, and the views of the pristine mountains are simply spectacular. Since it is the peak season for trekking, the trail becomes very crowded; hence pre-booking for the accommodation is recommended.
Spring is the second-best time to go Annapurna Circuit Trekking. Since spring starts after the cold winter, the trails become free from snow, the weather is pretty warm, blooming rhododendrons and other flowers beautify the trail, and the sun shines bright. Like in autumn, a massive crowd is on the trail, so pre-booking for the accommodation is recommended.
You can also go on this trek during the summer. So, if you want to view greenery or wildflowers in their undisturbed natural environment, this might be the best time. As with the rest of the year, the day is slightly warm, making it an excellent season for trekking activities.