NZ struggles under sticky, hot blanket
Many Kiwis finding humidity a challenge but MetService says the end is in sight
If the muggy nights have been keeping you up you’re not alone. Parts of the North Island — and even Christchurch in the south — hit 99 per cent humidity yesterday. Tauranga and Rotorua were at 99 per cent humidity about 8 last night while Wellington was at 96 per cent. Auckland was at 90 per cent humidity.
Temperatures have been hovering in the low 20s in Auckland and Tauranga in the past few nights making for sticky conditions, with more of the same forecast in coming days.
For Auckland and Northland the humidity is expected to be up to 97 per cent today, falling to the high 80s then up to the high 90s tonight.
MetService lead meteorologist Mark Todd said the tropical weather is making New Zealand feel “more like the Cook Islands at the moment”.
Warm, humid air is being dragged down from the subtropics, keeping temperatures high and nights muggy.
Soul Bar and Bistro owner Judith Tabron said her workers are finding it hotter than usual. “I am constantly finding my staff in the cool room.”
Last night the bar shut the doors and put the air conditioning on — for the first time in 17 years.
Kiwis have been flocking to buy fans and dehumidifiers in the heat.
Noel Leeming executive general manager merchandise Jason Bell said fans have been in popular demand nationwide this summer, with sales more than double that of the same period last year.
“However, over the last week or so with the arrival of some rainy and humid weather, fan inquiries have started to slow and popularity has spiked for dehumidifiers.”
Much of the North Island is in for another hot night tonight with an overnight low of 21C forecast for Tauranga while Auckland, Whangarei and Rotorua can expect a slightly cooler 20C and Hamilton 19C.
But MetService expects the mugginess won’t hang around the North Island for too much longer.
A band of heavy rain is forecast to hit the island’s upper half today and possibly thunderstorms too, especially in western Bay of Plenty, Rotorua, Waikato, Waitomo and north Taupo.
A few showers are expected to linger over the island later in the week, but generally much drier and finer conditions are expected. Why do we feel mugginess? When subtropical air masses arrive over New Zealand — especially in the north — they pack enough moisture to drive humidity levels up. Aucklanders awoke to near 100 per cent humidity yesterday but a better measure of that mugginess we feel is called the dew point. That’s the temperature at which, if cooled, water vapour from the air would condense on to a surface such as grass. This requires 100 per cent relative humidity and occurs when the air temperature equals the dew point. We really begin feeling clammy when the air is both warm enough to make us sweat — but carries enough water vapour to interfere with that process. So how does that work? When temperatures rise, humans shed heat through the evaporation of sweat from our skin. But humidity compromises our ability to do so. Because our sweat is essentially filtered blood — and it’s the plasma of our blood that leaves through our sweat ducts — our bodies lose fluid that could have been used elsewhere, which leaves us feeling sapped of strength and energy. Our bodies adapt after just a few weeks by sweating more efficiently. Why is it so hard to sleep? During the night, heat can increase how long it takes to get to sleep, and the number of times we wake. The sleep hormone melatonin helps regulate the sleep cycle by dropping