Weather in Wellington in May

Shoulder season. May is shoulder season in Wellington — cheaper, quieter, and a genuine gamble. Highs sit at 14.4 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

May ranks 7 of 12 in Wellington: past the worst of the year but short of February, which is the month to book if the dates are open.

Rain on 12 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 14.4 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 3.1 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest May day reached 19.1 °C and the coldest night fell to 6.4 °C, and the wettest single day dropped 38 mm — roughly 48% of the month's rain in one day.

May is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest May on record still delivered 134 mm against 38 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 80 mm average is a reasonable planning figure, not a promise.

Wind sits around 19.2 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 84%, which at 14.4 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How May sits in the year

The month is on the way down: 1.8 °C cooler than April, with June dropping another 2 °C. The first week and the last are not the same trip.

Daylight in May

9.9 hours of daylight, losing 1 hours across the month. That is between Wellington's extremes of 15.1 and 9.2 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 13.8 °C in May — too cold to swim without a wetsuit. The sea peaks at 16.8 °C in February and bottoms out at 11.6 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Wellington versus nearby

If Wellington is one option among several, the nearby comparison is worth making. Nelson is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Palmerston North is close enough to be a coin toss — within a degree on temperature, 3 days more rain.

So: May is a compromise. February is 24 points better and is what Wellington is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Wellington

See all twelve months in Wellington, or where else to go in May.