FAQ - Seasonal Variation
Weather at Aoraki Mount Cook is best described as "variable and vigorous", with considerable precipitation at times. There is also marked seasonal variation. This section describes the changes you can expect between seasons, with weather, temperature and conditions underfoot. It also discusses some specifics with clothing selection for different. For details on specific gear and clothing selections see the Gear Guide section of the FAQ.
Summer Mountaineering Conditions
The summer climbing period extends from November to early-April. You must be prepared for a wide range of conditions, from very warm, to cold snowy days. As the summer season advances access on to climbing routes will change.
Summer Temperatures and Daylight Hours
Actual air temperatures may be 8°C, but can feel like 28°C due to reflected radiation.
- Coolest period: November to mid-December, and March-April. Range -10°C to +10°C
- Warmest period: January and February. Range -5°C to +15°C
- Daylight hours: 05:00 to 21:00, with shorter days later in the season.
Changing Snow Conditions
During November and December access on to routes is usually easier, due to fewer crevasses. Expect fresh snow during storms. Your guide will place greater emphasis on avalanche awareness. Avalanche transceivers are normally carried.
The snowpack is deeper and "wetter". Conditions can be soft underfoot early in the season, especially in the afternoon.
From January onwards the snowpack will consolidate (shallower foot penetration). Crevasses are larger. Crevasse bridging is weakest. Less chance of snowfall. Rock fall hazard increases.
Late Season - March onwards: Conditions are typically "hard" underfoot. Crevassing is at its greatest extent. Night temperatures are dropping. Greater chance of snowfall.
Winter Mountaineering Conditions
The winter mountaineering period extends from July to mid-October (approximately). During winter daylight hours are shorter, weather is colder, and snow cover is at its maximum extent. Deep snow is common.
Travel on foot is difficult at times, unless aided by skis, snowshoes, or split-snowboards. All AGL parties carry avalanche transceivers. Avalanche awareness and rescue is a focus of winter trips.
- Coolest period (winter): July/August. Range -15°C to 0°C
- Warmest period (spring): September/October. Range -10°C to +5°C
- Daylight hours: 08:00 until 17:00
Winter Period (July/August)
Early winter offers a greater likelihood of powder skiing. Days are short and temperatures coldest – perfect for keeping your powder dry. Less terrain may be accessible due to snow stability/avalanche conditions.
Spring Period (September/October)
It is not uncommon to ski powder after a spring storm, but you are more likely to find corn snow. Corn is better suited to first time backcountry skiers.
Daylight hours are longer and warmer. Snow cover is at its maximum. More terrain can be accessible due to better stability/avalanche conditions.
How to Dress | Gear for Different Seasons
Choose your mountain wardrobe around the time of year you visit. Mountain huts in NZ are generally not heated. Temperatures are colder at night, even during summer. If your trip involves camping out go for the warmest possible combination of clothing.
Summer Gear (November - April)
There is a wide range of temperatures through summer. Be prepared for cool, to cold temperatures during storms and at night. Choose:
- 3-season sleeping bags (rated to approx -5°C)
- 400-500 loft down jackets or synthetic insulating jackets
- Lightweight to mid-weight thermals and socks
- UV Protection is Vital
Through January and February especially bring "cooling" garments that will reflect UV. For example; glacier shirts (light colours/quick drying), legionnaire hats, scarves, and neck gaiters (e.g. "Buff").
Winter Gear (July - October)
- Warmer down (500+ loft) and synthetic jackets
- Medium to heavy grade thermals and socks
- Warm, insulated gloves
- 4-season sleeping bags (rated to approx -12°C)
Avoid using drinking bladders and hoses during winter - they are prone to freeze even when insulated.