Benmore Peak Observatory
New Zealand
44° 25’ S 170° 05’ E
6,338' (1,932 meters) ASL
Q. "It was so hot/cold at my place recently I think we set a new record! Who do I inform?"
A. The highest temperature ever recorded in New Zealand was 42.4 °C at Rangiora and Jordan
on February 7th, 1973. The lowest was -21.6 °C at Ophir, on July 3rd, 1995. If you believe you
have exceeded these values, and your temperature sensor has been properly calibrated, and
is housed within a 'standards compliant' Stevenson screen, call the New Zealand Met Service.
The bad news is that they are unlikely to be very interested, unless you are an official Met Service
observer, and/or using Met Service-approved instrumentation. Readings taken from a domestic
glass thermometer hanging on a wall at your place is of little value, since it is almost certain to
be inaccurate (and therefore must be assumed inaccurate). Refer to this page for more information.
Q. "Why isn't the [Insert name of...] weather station online yet?"
A. Unfortunately we just haven't had time to get them all online yet. This is an entirely voluntary
endeavour (ie we charge nothing for the service), and we have "real" jobs, so there's been little time
available to travel the often long distance required to get them all completed. We apologise, and
hope to have these stations, and a few more, online soon.
Q. "I'm also in [Insert placename...]: Why does my thermometer read higher in summer
and lower in winter than yours?"
A. Because our temperature sensors are protected by a Stevenson screen. This is a
wooden double-louvered box, painted bright white to reflect as much sunlight as possible.
It is sited 1.5 meters above an expanse of mown grass. This means the instruments are
protected from the elements but can accurately record the ambient air temperature
without being affected by direct solar radiation or other environmental factors.
Most domestic (and many commercial) thermometers are poorly sited. For reliable and
accurate readings, the instrument must be shielded from direct sunlight at all times,
and isolated from metalwork, glass, brick, concrete or masonry.
In summer, direct sunlight and reflected or reradiated heat from metal, glass or masonry will
cause the thermometer to display readings higher than the actual ambient air temperature.
In winter, moisture from the slightly warmer air will condense onto the cold exposed glass
thermometer and freeze, causing the instrument to display readings lower than the actual
ambient air temperature.
The thermometers common in modern vehicles are seldom accurate, and should be used
as a guide only. They are adversely effected by engine heat. If your in-car instrument is
reading 45 °C while driving hard in direct sunlight, you should consider that to be at least
10 °C higher than the actual ambient air temperature.
Please take all these factors into account before contacting us to report our "faulty" readings!
Remember, if you're not able to adequately shelter your thermometer, the temperature it
displays must (and will) be considered inaccurate.
Benmore Peak Observatory's weather stations are not official NZ Met Service or NIWA sites,
and we accept no responsibility whatsoever regarding forecasts or readings. However all of
our weather station instruments are precisely calibrated, and checked regularly.
Q. "I don't care what you say about using properly protected and approved instruments,
I just KNOW it was hotter/colder than you, NIWA, the NZ Met Service, and the TV weather
person claim it was!"
A. Fine. You can believe whatever you wish, and most people do. Why let the facts get in the way
of a good story? If it helps you sleep at night believing that you live in a hotter or colder place than
your brother-in-law we're very happy for you. Just don't expect to be taken seriously when you tell
us that it was 60 °C, or -40 °C, or that 900mm of rain fell in 10 minutes at your house, unless you
live in Qatar or Alaska, and even then we'd want to see proof! :-)
Q. "There's no need to be abusive! All I'm saying is that your weather readings are wrong,
because my sister's cousin's friend's uncle's dog's groomer's wife's psychic knows that it
was [Insert absurd figure...], and not what your weather station reported, and obviously I
have no reason to doubt such a reliable source!
A. Look, here's the thing...if you place your thermometer in the oven for three hours, does that
mean it's 400 °C in your kitchen? No? In that case, why would you believe the readings from a
thermometer which has been out in the sun all day to be indicative of the actual outdoor air temperature?
There's a reason we take temperature measurements "in the shade". Things sited out under the sun get
hot. This results in completely inaccurate data, unless the goal is to study the effects of prolonged
solar exposure on thermometers.
The same can be said for readings taken from other inappropriate places, such as steel roofs, or
concrete shopping malls: the data collected has absolutely no usefulness. Business groups lobby to
have their city's or town's weather stations hidden away in sun-lit gullies because they are convinced
that the resulting exaggerated temperatures will lure hordes of tourists to town and make the business
group's members rich.
For the sake of scientific accuracy, integrity, and just plain honesty, we must exercise good sense
and site weather instruments in sensible locations, as it's the only way to collect reliable, consistent
and useful data.