Weather Watch: Cloud makes getting up easier

Photo / HoS.

Wow what a difference the cloud and/or wind made this morning to the temperatures - a huge jump in overnight lows, by up to 10 degrees for some and the next two nights/early mornings look similar too.

It made climbing out of bed a little easier. But the grey skies, certainly where I am in Auckland, followed by rain has meant a cold day even if the air temperature is the same as it was when it was sunny yesterday. It's a funny thing, how the "feels like" temperature is so different to the actual temperature.

You increase the humidity or the wind and bam, it can feel totally different.

A good example of this is in America today. The second heat wave in two weeks is hitting parts of the country, this time the mid-west. Chicago had a feels like temperature of 46 degrees today - that's Celsius. The air temperature was in the 30s. But with high humidity coming off the Gulf of Mexico, coupled with baking hot land underneath, the two combined to make it unbearably hot. Chicago has a history of heatwaves - they are deadly. In fact, heatwaves kill more people than any other severe weather events. Overnight lows in Chicago have been around 27 degrees which is also unbelievably hot.

WeatherWatch.co.nz uses the humidex readings in summer when it's important. Some conservative weather observers disagree with the methods - but at the end of the day it's all subjective. Today I'm "kinda cold" but wearing a t-shirt. A friend of mine is "freezing" and wearing a jacket, hat and scarf.

I believe temperatures should also be taken from areas with polluted heat and cold - by that, I mean placed in the middle of the city where buildings and streets and vehicles and air conditioning units emit plenty of extra heat. Or in windy, cold, streets or exposed waterfronts. After all, the majority of us live in towns and cities... so why not also include non-scientific temperatures to help us with our days.

In winter we use the wind-chill. This is when we have a temperature below 10 degrees usually, with a bitterly cold southerly that drops the temperature even further if you're standing in it. It's the complete reverse of the humidex but it has the same result - giving us a temperature that perhaps better reflects the weather for us.

However this winter we haven't had a lot of cold wind to really use the wind chill. It's pretty pointless using it when it's 14 degrees...as the wind chill will probably only be 11 or 12. But if you have a temperature of 6 with a roaring cold southerly, it may feel more like -4. This winter we have lacked those Antarctic southerlies... most of our cold weather has been generated by overnight lows. The highs have been normal if not above normal - certainly in the North Island. Yesterday Tauranga made it to 18 degrees...again!

Winter isn't over yet...but I'm pretty confident we'll see a slightly warmer than average winter this year, especially in the North Island.