New Zealand Weather

I was in NZ during their summer - December 2019 - for three weeks, and it was barely warm enough for shorts! There were stories on TV about people going to the beach and going swimming, but it felt much too cool for that to me. Unless we were there during a flukey cold year, it seemed like the country never got hot. We did both the North and South islands, from tip to tip, so you can't say we missed the warm part of the place.

We visited Australia and NZ in April of 2018 and were surprised that the weather in NZ was significantly colder than Australia.

We were in NZ in January-February 2020. We were also watching the weather for Australia during this time because we were heading to Melbourne for our last week. While in and around NZ, from Auckland to Milford Sound we wore layers but had some warmer days too—never hot. It didn’t seem to be too humid. Meanwhile in Australia’s the temperatures were over 100° many days and we were sure we’d really need the most warm weather clothes we brought. By the time we got to Melbourne it was so cool we wore a jacket most evenings and never broke out the shorts. When you get ready to go, study historical temperatures but look carefully at the 10 day forecast In several places and take little layers from the northern tip of NZ to the southern tip.

We visited friends in the North Island a number of years ago. We were there mid Feb.-March. The temperature was moderate and pleasant. If we were to return we would go at the same time. Fond memories.

We've been to NZ numerous times, most recently a 10 week trip over Feb & March a couple of years ago. It's always nice, but especially so during the height of their summer.
Check the historical weather trends for cities like Auckland, Queenstown and Christchurch to see what their averages are, but the nice thing is that wherever you go in the country it'll be relatively cool, ie daily highs in the 70's and cooling off nicely in the evenings, so any humidity you encounter won't feel as oppressive as other, hotter destinations.
The country is about the size of the state of California - stretching nearly 1,000 miles from the tropical North Island to the tip of the South, so local conditions will vary dramatically depending on where you choose to base yourself. The Canterbury Plain area in the central part of South Island sits in the rain shadow of the Southern Alps, so places like Wanaka, Mt Cook, Queenstown and Christchurch will be very nice indeed during that time of year.
Aside from the weather, know that Feb/March is a popular time for visitors from mainland China, Taiwan & Singapore who flock there during the Chinese New Year celebrations which begin around the end of January and can last well into March. During our most recent visit the more popular visitor destinations (Queenstown, Mt Cook, etc) were overrun to the extent that it was difficult to find a place to stay in some of the smaller towns if you hadn't booked well in advance. Most of the popular tourist activities (bungee jumping, zip lining, jet boat excursions, etc) tended to be pretty clobbered too, though the hiking trails were still mercifully crowd free - even the more popular multi-day hikes.
Once the holiday period ended in mid-March we noticed a dramatic reduction in the crowds, so you might want to crank that into your planning.

Kia ora! I think the question has been answered pretty well by others but just to add my tuppence worth as an adopted Jafa (Just Another Friendly Aucklander).. Feb/March is the tail end of summer here. Over recent years it has been getting hotter later in the summer. Generally the hottest months are December and January but this is changing. As already mentioned there are great variations in temperature in New Zealand. The top two thirds of the North Island are in a sub-tropical region. The west coast of the south island has glaciers and there are mountainous regions and winter ski-fields in both islands. Auckland is quite humid. If you don't like heat and humidity consider going later in March.

Hi, canoop. I also hate hot, humid weather. I learned a long time ago to ask people who are telling me the temp is "nice" or "warm" what temperature they are talking about. All too often, people define temps in the 80s as "warm." To me, that's too hot, and 75 deg F is way too hot if it's humid! So, different strokes for different folks. I spent 2-1/2 weeks on the South Island a few Aprils ago, and I really loved the weather. It was mostly in the 50s or low 60s F during the day, and it dipped into the 20s F at night. Didn't rain much at all. I had to get my head about seeing gorgeous red and yellow autumn leaves, which kept reminding me that I was indeed in the southern hemisphere. Not humid at all, and at least the year I went, no hordes of tourists. As a couple of others noted, you'll experience a temp difference between Christchurch and Queenstown, and between the North Island and the South. I loved NZ. Beautiful country, friendly people.