Monthly weather averages & travel planning

South America › 🇨🇱 Chile › Santiago
Updated: March 2026
December is a excellent time to visit Santiago (8/10). With 14 daily sunshine hours and only 1 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 2nd sunniest of the year in Santiago. Beach and outdoor-focused visitors will find December ideal, though hotel prices reflect demand and popular sites get crowded by mid-morning. November offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Santiago'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: book accommodation at least 6-8 weeks ahead, as popular hotels fill quickly during December. Purchasing skip-the-line tickets for major attractions in advance saves meaningful time. If you have flexibility, arriving a few days before or after peak weekends reduces both crowds and prices noticeably.
December weather in Santiago is defined by a daily temperature swing from 15°C at night to 27°C during the afternoon. Humidity averages 70%, and you can count on around 14 sunshine hours each day. That combination makes December warm and lush, though dressing in breathable fabrics keeps things manageable.
27°C
81°F
Avg High
15°C
59°F
Avg Low
1 days
7 mm total
Rain Days
14h
per day avg
Sunshine
70%
Moderate
Humidity
The 12°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. Humidity averages 70%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 9 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Winds are calm at an average 13 km/h, so wind-chill is not a factor in planning your clothing. In Fahrenheit: 81°F average high, 59°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Packing for Santiago in December means dressing for 27°C days and 15°C evenings. A light cotton tee with a casual overshirt works well at 27°C, the overshirt doubles as a layer for air-conditioned venues. Evenings drop 12°C to around 15°C, a notable shift that catches underprepared visitors off guard. Pack a dedicated evening layer. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues.
Local tip: Layers are more practical than a single heavy garment in Santiago. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.
December has no major festivals or public holidays in Santiago, 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 27°C average highs and 1 rainy days
December in Santiago reflects a mid-latitude climate pattern, with temperatures averaging 27°C by day and 15°C overnight. The city sits at 33 degrees south latitude, where the balance between solar radiation and heat loss drives conditions that are neither extreme nor static. The warm temperatures reflect a stable high-pressure pattern typical of the season, which suppresses cloud formation and concentrates solar energy at the surface. Day-to-night temperature variation of 12°C is moderate and manageable with a single mid-layer. 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.
Santiago in December
December ranks 2nd sunniest of the year in Santiago, with an average 14 daily sunshine hours. The driest months are January, February, and March. January is the hottest month (28°C avg high); June is the coolest (15°C). From here, temperatures rise 1°C into January. Compared to last month (November: 24°C high, 3 rain days), December is warmer and drier. December is among the top three sunniest months to visit Santiago.
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 28°C | 17°C | 1 | 14h | View |
| February | 28°C | 16°C | 1 | 13h | View |
| March | 26°C | 15°C | 1 | 12h | View |
| April | 22°C | 11°C | 3 | 10h | View |
| May | 19°C | 7°C | 6 | 8h | View |
| June | 15°C | 5°C | 7 | 7h | View |
| July | 15°C | 4°C | 7 | 8h | View |
| August | 16°C | 5°C | 8 | 9h | View |
| September | 18°C | 7°C | 8 | 10h | View |
| October | 20°C | 9°C | 6 | 12h | View |
| November | 24°C | 12°C | 3 | 13h | View |
| December | 27°C | 15°C | 1 | 14h | View |
January
1 rain days, 14h sun
February
1 rain days, 13h sun
March
1 rain days, 12h sun
April
3 rain days, 10h sun
May
6 rain days, 8h sun
June
7 rain days, 7h sun
July
7 rain days, 8h sun
August
8 rain days, 9h sun
September
8 rain days, 10h sun
October
6 rain days, 12h sun
November
3 rain days, 13h sun
December
1 rain days, 14h sun
Data Sources for Santiago
Climate normals represent 30-year averages (1991-2020). Individual years may vary.