The dry season
April through November is when conditions are at their best. Weather is predominantly dry, trails are firm, and summit views are clear. Temperatures at base camp range from 10 to 15°C at night and around 25°C during the day. At the summit, expect 0 to 5°C before dawn.
Month by month
April
The park reopens. Trails are fresh and green from the rains. Occasional afternoon showers are possible in the first two weeks as the wet season tapers off. Mornings are usually clear. Fewer trekkers means quieter camps and more flexibility with dates.
May
Dry weather settles in. Skies are clearer than April. The landscape is still lush from the rains. One of the best months for photography. Crowds remain low. A good window for trekkers who want the mountain to themselves.
June
Dry and stable. European summer holidays begin to bring more visitors. Trail conditions are excellent. Temperatures are comfortable. Book a week or two ahead to secure your preferred dates.
July
The driest month. Clear skies almost every day. Summit sunrise views are at their best. This is also the busiest month. Camps are fuller. Trails are more crowded, especially near the crater rim. Book well in advance.
August
Conditions mirror July. Dry, clear, and busy. Indonesian domestic holiday (Independence Day, August 17) adds to the numbers. The best weather but the least solitude. Book at least two to three weeks ahead.
September
Summer crowds thin out. Weather stays dry and reliable. Temperatures are slightly warmer than July-August. An excellent month — peak conditions without peak crowds. One of the team's personal recommendations.
October
Still mostly dry. Occasional clouds build in the afternoon as the wet season approaches. Mornings remain clear. Fewer trekkers. Good value and good conditions. The transition is gradual — early October is more reliable than late October.
November
The transition month. Rain becomes more likely, especially in the second half. Some treks may be delayed or rerouted depending on conditions. Trails can be slippery. Still trekable, but bring a rain jacket and lower your expectations for sunrise clarity.
December to March — the wet season
December — March
Wet seasonHeavy monsoon rain. Trails are slippery and muddy. River crossings swell. Landslides are a real risk on the steep volcanic slopes. Visibility drops and summit sunrises are often obscured by cloud. Trekking is possible but significantly more demanding and less predictable. The dry season is strongly recommended for most trekkers.
If your travel dates fall in the wet season, talk to the team first. They know current trail conditions and will advise honestly on what is feasible.
Quick summary
- Best weather: July and August
- Best balance (weather + fewer crowds): May, September, early October
- Budget-friendly: April, October, November — see full trek cost breakdown
- Wet season: December through March (possible but challenging)
Book your dates
Popular dates fill weeks in advance during peak season. Off-peak months are more flexible. Either way, message the team early and they will hold your spot.