The best time for a week-long trip to Bhutan is generally during the spring (March to May) or autumn (September to November). These seasons offer the most pleasant weather with clear skies, mild temperatures, and vibrant landscapes, making them ideal for sightseeing, trekking, and experiencing Bhutan's rich culture.

Here's a more detailed breakdown:

Spring (March to May):

• Weather: Pleasant and mild, with temperatures ranging from 8°C to 24°C (46.4°F to 75.2°F). You can expect mostly dry conditions and clear blue skies, although occasional short showers are possible, especially in May.
• Scenery: This is a beautiful time as the valleys come alive with blooming flowers, including the famous rhododendrons that carpet the hillsides in various colors, typically peaking from late April to May. The landscapes are lush and green.
• Activities: Spring is excellent for all outdoor activities such as trekking, hiking, rafting (rivers have good water flow from snowmelt), and cycling. It's also a great time for birdwatching.
• Festivals: Several colorful festivals (Tshechus) often take place during the spring months, offering a chance to witness Bhutanese culture and traditions. The Paro Tshechu, usually in late March or early April, is one of the most popular.
• Crowds & Costs: Spring is considered a peak tourist season, so expect more visitors and potentially higher prices for accommodations and flights. Booking well in advance is recommended.

Autumn (September to November):

• Weather: Characterized by sunny days, clear blue skies, and crisp, cool air. Temperatures generally range from 7°C to 25°C (44.6°F to 77°F). Rainfall is minimal, and humidity is low, offering excellent visibility of the Himalayan peaks.
• Scenery: The landscapes are stunning with golden hues as the rice fields ripen, and the surrounding hills take on autumnal colors. The air is fresh and clean.
• Activities: Autumn is another prime time for trekking and other outdoor adventures. The clear weather provides magnificent views. It's also a popular time for cultural tours and sightseeing.
• Festivals: Autumn also hosts several significant festivals, including the Thimphu Tshechu (usually in September or October) and the Jambay Lhakhang Drup in Bumthang.
• Crowds & Costs: Similar to spring, autumn is a peak tourist season, so expect higher prices and more visitors. Early booking is essential.

Other times to consider (with potential drawbacks):

• Summer (June to August): This is the monsoon season in Bhutan. While the rain is not usually continuous downpours, you can expect frequent showers, especially in the afternoons and evenings. Trekking conditions can be challenging due to muddy trails and potential landslides. However, the landscapes are incredibly lush and green, and there are fewer tourists, which can offer a more intimate experience. Some summer festivals occur in less-visited regions.
• Winter (December to February): Winter in Bhutan is cold, with temperatures potentially dropping below freezing, especially at higher altitudes. Snowfall is common in the northern regions and can block some high mountain passes, affecting trekking. However, the skies are often clear, offering stunning views of snow-capped mountains. There are fewer tourists, and you might find lower rates for accommodations. It's also the season to see the endangered black-necked cranes in the Phobjikha Valley (from late October to mid-February).

For a week-long trip, considering factors like pleasant weather, accessibility, and a range of activities, spring (March-May) and autumn (September-November) are the most highly recommended times.

To make the most of your week, it's beneficial to align your travel dates with any specific interests you might have, such as attending a particular festival or seeing the rhododendron blooms at their peak. Remember to book your trip well in advance if you plan to travel during the peak seasons.