Umbrellas, jackets, t-shirts and sunscreen make up the forecast for the rest of this week says WeatherWatch.co.nz as a system that brought isolated flooding to parts of south eastern Australia drifts towards New Zealand.

Heat and humidity will today combine to make “feels like” temperatures in the late 20s and low 30s across parts of New Zealand – even if your daily high is only in the low to mid 20s. This will happen if you get plenty of sun to help heat the air first.

It’s this daytime heating which could trigger thunderstorms and torrential downpours across northern and western regions of the North Island later today. WeatherWatch.co.nz says downpours may be heavy enough to cause localised surface flooding and could make driving hazardous.

But our chaotic summer weather pattern remains in place – while some communities could be hit by rainfall rates heavy enough to flood drains and cause surface flooding, a kilometre away it may only be drizzling. Another kilometre away it may be still sunny.

This is the nature of this fairly weak low that is moving in – the cloud mass surrounding it is very much alive, shrinking and growing all the time – and it’s this constant change that makes it tricky to time things and to be more specific.

As we head into Wednesday we’ll be left with a similar forecast to Tuesday, heavy downpours for some – especially inland where the heating will help – while lighter showers and drizzle may be experienced elsewhere.

The North Island will receive the bulk of the rain, while southern and eastern areas of the country should be driest.

Humidity will work with the heat this week to make conditions feel hotter than they are says WeatherWatch.co.nz.

The humidex, which works out the air temperature combined with humidity to create a somewhat subjective feels like temperature – is calculating that although highs will only be in the low to mid 20s this week, the feels like temperature will be in the late 20s and low 30s at times for some who get the sun.

WeatherWatch.co.nz exclusively uses the humidex temperatures, also used by the public forecaster in Canada.  It’s most accurate for inland areas away from sea breezes where highs climb into the late 20s and humidex readings can climb upwards to 40 degrees.

While high humidity is common all year round in New Zealand, it’s the summer humidity that makes conditions feel muggy.

So far this summer we’ve had some very humid days, but without the heat many people haven’t really been aware of it.

In winter high humidity is normal, but with cooler air we tend to only notice it as damp air, which makes mould in many homes.

In summer the same humidity levels coupled with heat can make small physical tasks difficult, make our skin sticky and make sleeping hard.

For those who don’t have heat pumps with the air con feature, a simple cheap fan pointed at your body can be very effective – by producing a localised wind chill factor on your body. Coupled with slightly damp skin it can be incredibly refreshing.

Opening windows only helps if there’s a breeze – or if the temperature outside is lower than indoors…and sometimes in summer, it isn’t.

This week we’ll see overnight lows between 18 and 20 degrees for the upper North Island – which will make a humidex temperature in the low to mid 20s for some who have no breeze.

– Homepage image / File, AJ Barnes

– WeatherWatch.co.nz