Summer in New Zealand typically runs from December through February, with those months constituting the prime window for warm, sunny conditions across most regions. However, exact weather can vary by location, and definitions of "summer" can differ depending on whether you use meteorological, astronomical, or weather-pattern-based conventions. Here’s a concise guide to what that means for NZ:

• Meteorological summer: December, January, February. This is the most commonly cited frame for travel planning and statistics, aligning with consistent temperature patterns and daylight—great for beaches, hiking, and outdoor activities.
• Astronomical summer: Begins with the summer solstice (around December 21–22) and ends with the autumn equinox (around March 20–21). In practice, most people still think of peak summer as December–February in NZ.
• Regional variation: The North Island generally experiences milder, warmer summers and more humidity, while the South Island can have cooler days with higher variability, and alpine regions may see cooler nights even in summer.

Practical tips for planning:

• If you want consistently warm beach weather, aim for December–February, especially in places like Auckland, Tauranga, Wellington, and coastal South Island locations.
• For outdoor adventures without peak heat, late February can still feel summery but a bit less crowded.
• If you’re after festival-season energy and long days, December through February is NZ’s peak season.

If you’d like, I can tailor this to a specific city or activity (beaches, hikes, or ski-season crossover), or pull current seasonal averages for your exact destination.