Roseau in September

September weather, activities, events & insider tips

September Weather in Roseau

32°C (89°F) High Temp

24°C (75°F) Low Temp

0.0 mm (0.0 inches) Rainfall

70% Humidity

Is September Right for You?

Advantages

Post-hurricane season stability - September marks the end of the active Atlantic hurricane season, with significantly lower risk of major storms disrupting travel plans compared to July-August
Perfect whale watching conditions - Sperm whales are most active in Caribbean waters during September, with 85% visibility rates just 1.6 km (1 mile) off Roseau's coast
Ideal hiking temperatures - Morning temperatures of 24°C (75°F) create perfect conditions for tackling Morne Trois Pitons trails before midday heat sets in
Shoulder season pricing - Hotel rates drop 25-40% compared to peak winter months, with flights from North America averaging 30% less than December-March rates

Considerations

Variable rainfall patterns - While total rainfall is low, the 10 rainy days can be unpredictable, with sudden downpours lasting 45-60 minutes that can disrupt outdoor activities
High humidity levels at 70% - The combination with 32°C (89°F) temperatures creates a heat index that feels like 35°C (95°F), making midday activities challenging
Limited festival activity - September falls between Carnival season and Independence celebrations, offering fewer cultural events compared to other months

Best Activities in September

Sperm Whale Watching Expeditions

September offers the Caribbean's best whale watching with sperm whales most active in deep waters just 20 minutes from Roseau. The post-hurricane season brings calmer seas and crystal-clear visibility. Morning departures at 8:30am avoid afternoon heat and take advantage of cooler 24°C (75°F) temperatures. Success rates reach 85% in September compared to 60% in other months.

Booking Tip: Book 7-10 days ahead for best boat selection. Tours typically cost XCD $135-180 (USD $50-65) and last 3 hours. Look for operators with hydrophone equipment and certified marine biologists. Morning tours fill quickly due to optimal conditions.

Rainforest Canopy Adventures

September's variable weather creates dramatic cloud formations over Morne Trois Pitons, offering spectacular canopy views between rain showers. The 70% humidity keeps vegetation lush while morning temperatures of 24°C (75°F) make zipline tours comfortable before 11am. Recent trail improvements in 2025 include new platforms with panoramic views.

Booking Tip: Book morning slots (8am-10am) to avoid afternoon heat and potential showers. Expect to pay XCD $160-220 (USD $60-80) for 3-hour canopy tours. Choose operators with multiple backup dates due to weather variability.

Champagne Reef Snorkeling

September's calm post-hurricane seas create ideal conditions at Dominica, where volcanic vents create underwater bubble streams. Water temperatures hold steady at 28°C (82°F) with 25m (82ft) visibility. The site is protected from September's variable winds, making it accessible when other dive sites close.

Booking Tip: Half-day trips cost XCD $80-120 (USD $30-45) including equipment. Book with operators offering flexible rescheduling for weather. Afternoon tours (1pm-4pm) often have better underwater lighting in September.

Trafalgar Twin Falls Hiking

September's recent rains ensure maximum water flow at the twin waterfalls while morning temperatures of 24°C (75°F) make the 1.2 km (0.7 mile) moderate hike comfortable. The hot springs at the base provide perfect relief after hiking in 70% humidity. Trail conditions are excellent following 2025 maintenance upgrades.

Booking Tip: Start hikes by 8am to complete before midday heat. Guided tours range XCD $65-95 (USD $25-35) for half-day excursions. Independent hiking requires XCD $13 (USD $5) park entrance fee. Waterproof shoes essential for wet rocks.

Scotts Head Marine Reserve Diving

September offers exceptional diving at Dominica Peninsula where Atlantic and Caribbean waters meet. Volcanic underwater landscapes feature dramatic drop-offs to 30m (98ft) with water temperatures at 28°C (82°F). September's reduced tourist numbers mean uncrowded dive sites and better marine life encounters.

Booking Tip: Two-tank dives cost XCD $190-250 (USD $70-90) with equipment. PADI certification required for look ats. Book 5-7 days ahead with operators offering small group sizes (maximum 6 divers). Weather backup plans essential.

Boiling Lake Expedition

September's cooler morning temperatures make the challenging 13 km (8 mile) round-trip hike to the world's second-largest hot spring lake more manageable. The trail through Valley of Desolation showcases post-rain volcanic activity with increased steam vents and sulfur springs. Requires excellent fitness and full-day commitment.

Booking Tip: Mandatory guide service costs XCD $270-350 (USD $100-130) for groups up to 4 people. Book 10-14 days ahead - only certified guides allowed. Start at 6am to avoid afternoon heat and weather. Requires overnight gear if weather delays return.

September Events & Festivals

Early September

Feast of Our Lady of Fair Haven

Local Catholic celebration honoring the patron saint of fishermen with colorful processions through Roseau streets and traditional blessings of fishing boats. Features local food vendors, traditional music, and cultural displays showcasing Dominican maritime heritage.

Essential Tips

What to Pack

Quick-dry hiking boots with aggressive tread - essential for wet volcanic rocks at waterfalls and trail conditions during September's 10 rainy days

SPF 50+ reef-safe sunscreen - UV index reaches 8 and Caribbean sun reflects intensely off water during whale watching and snoreling activities

Lightweight merino wool clothing - stays comfortable in 70% humidity unlike synthetic fabrics that trap moisture and odors

Packable rain jacket with hood - afternoon showers in September last 45-60 minutes and arrive with little warning, especially in rainforest areas

Waterproof phone case - essential for whale watching boats and waterfall hikes where spray and sudden rain can damage electronics

Insect repellent with 25% DEET minimum - September's humidity increases mosquito activity, particularly at dawn and dusk hiking times

Electrolyte tablets or powder - 70% humidity and 32°C (89°F) temperatures cause rapid dehydration during outdoor activities

Grip-sole water shoes - volcanic rock at Dominica and Dominica becomes extremely slippery when wet

Portable battery bank - high humidity drains phone batteries faster, and remote hiking areas have no charging options

Anti-chafing balm - essential for hiking in 70% humidity where traditional clothing can cause uncomfortable rubbing during long walks

Insider Knowledge

Local buses run on 'island time' but are most reliable 7am-9am when drivers start fresh routes - perfect timing for morning activity departures to beat the heat

Roseau Market vendors offer best fruit prices on Thursday mornings when boats arrive from rural villages, and September mangoes reach peak ripeness

The Botanic Gardens near Roseau offer free shade and cooling during midday heat - locals use it as a meeting point and rest stop between 12pm-2pm

Cellular coverage drops significantly above 300m (984ft) elevation on hiking trails, but emergency whistle signals carry far in September's dense, humid air

Avoid These Mistakes

Scheduling outdoor activities after 11am - September's combination of 32°C (89°F) heat and 70% humidity creates dangerous conditions for hiking and physical activities

Bringing only synthetic athletic wear - these fabrics become unbearable in Caribbean humidity and retain odors after one day of wear

Assuming clear morning skies mean no rain - September weather changes rapidly, with sunny conditions turning to downpours within 30 minutes