The best seasons to visit Bhutan are during Spring (March, April & May) and Autumn (September, October & November). The major Bhutanese religious festivals are held during these seasons and find Spring and Autumn weather make it an ideal time for trekking in Bhutan and for traveling throughout the country enjoying great views of Himalayan mountains peaks.
It is Bhutan government rule that total tour payment must be remitted without which the government will not issue your tour visa.So please do remit the full tour payment, in order to get your Bhutan visa processed.