Monthly weather averages & travel planning

South America › 🇵🇪 Peru › Cusco
Updated: March 2026
September is a good time to visit Cusco (6/10). With 11 daily sunshine hours and only 13 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 2nd sunniest of the year in Cusco. Culture-focused travellers and those who prefer lighter crowds will find September a practical choice, with prices running lower than peak August without sacrificing all the good weather. October offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Cusco's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
Planning a trip to Cusco in September? Days warm to 16°C on average while evenings hold at 6°C, giving you a clear sense of what to pack. The month delivers roughly 11 hours of sunshine per day and 38mm of rainfall spread across 13 wet days, so there is plenty of fair weather to work with.
16°C
61°F
Avg High
6°C
43°F
Avg Low
13 days
38 mm total
Rain Days
11h
per day avg
Sunshine
82%
Humid
Humidity
The 10°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. At 82% humidity, the 16°C daytime high feels 2-4°C warmer in practice: quick-dry fabrics and shade-seeking between noon and 3pm are the sensible response. UV index averages 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Winds are calm at an average 9 km/h, so wind-chill is not a factor in planning your clothing. In Fahrenheit: 61°F average high, 43°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Packing for Cusco in September means dressing for 16°C days and 6°C evenings. A mid-weight jacket over a sweater handles 16°C daytime temperatures; the combination stays comfortable all day without overheating. Evening temperatures settle at 6°C, a modest 10°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. With 13 rain days expected, a compact travel umbrella is worth the bag space. A waterproof jacket is better than an umbrella if you plan full-day outdoor routes. At 82% average humidity, quick-dry synthetic or bamboo fabrics dry overnight and stay comfortable longer than cotton.
Local tip: Layers are more practical than a single heavy garment in Cusco. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.
September has no major festivals or public holidays in Cusco, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
Based on 16°C average highs and 13 rainy days
In September, Cusco sits in the dry season corridor, as the ITCZ shifts away from the region and trade winds bring drier, more stable air. This produces reliably sunny days reaching 16°C, with lower humidity than the wet months. Overnight lows of 6°C offer a pleasant reprieve from the midday heat. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate, wear sunscreen. UV 6-7: High, hat and SPF 30+ essential. UV 8-10: Very High, limit midday exposure. UV 11+: Extreme, seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry, skin and throat may feel parched. 40-60%: Comfortable, ideal for most people. 60-80%: Sticky, light breathable fabrics recommended. Above 80%: Muggy, heat feels more intense; quick-dry clothing is essential.
Cusco in September
September ranks 2nd sunniest of the year in Cusco, with an average 11 daily sunshine hours. The driest months are June, July, and August. October is the hottest month (17°C avg high); January is the coolest (15°C). From here, temperatures rise 1°C into October. Compared to last month (August: 16°C high, 7 rain days), September is similarly warm and wetter. September is among the top three sunniest months to visit Cusco.
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 15°C | 8°C | 29 | 9h | View |
| February | 15°C | 8°C | 26 | 9h | View |
| March | 15°C | 8°C | 28 | 9h | View |
| April | 15°C | 7°C | 18 | 10h | View |
| May | 15°C | 6°C | 8 | 10h | View |
| June | 15°C | 5°C | 3 | 10h | View |
| July | 15°C | 5°C | 3 | 10h | View |
| August | 16°C | 5°C | 7 | 11h | View |
| September | 16°C | 6°C | 13 | 11h | View |
| October | 17°C | 8°C | 21 | 11h | View |
| November | 17°C | 8°C | 23 | 10h | View |
| December | 16°C | 8°C | 28 | 9h | View |
January
29 rain days, 9h sun
February
26 rain days, 9h sun
March
28 rain days, 9h sun
April
18 rain days, 10h sun
May
8 rain days, 10h sun
June
3 rain days, 10h sun
July
3 rain days, 10h sun
August
7 rain days, 11h sun
September
13 rain days, 11h sun
October
21 rain days, 11h sun
November
23 rain days, 10h sun
December
28 rain days, 9h sun
Data Sources for Cusco
Climate normals represent 30-year averages (1991-2020). Individual years may vary.