One of the big differences between a weather forecaster and a weather observer is the way that they value extremes.

Forecasting extremes of temperature or wind, or any other weather parameter, is very difficult indeed, so the forecaster is reluctant to do this whereas an observer, who is someone who just records what they see or measure, loves extremes.

I well remember being an observer at Filton airfield, near Bristol, in the 1963 winter, and getting very excited as the snow clouds cleared away allowing the temperature to rocket down to well below freezing.

Although it then felt very cold to us, those temperatures were nowhere near as low as on the icy plateaux of Antarctica where at the Vostok Station on 21 July 1983 the mercury plunged to -89.2°C or -128.6°F.

In contrast to this the highest shade temperature ever recorded, under normal circumstances, was 57.8°C, 134°F, at Al'Aziziyah, Libya, in September 1922. There is some doubt about this, and early maximum temperature records, due to the type of shaded screens that were used at the time. In fact, to be able to compare temperature readings across the Globe a standard measurement is needed.

To do this the thermometers are places 1 to 2 metres above the ground and sheltered from the sun in a screen that looks like a beehive. All the temperatures that are quoted are those in the shade, and this is why you sometimes get reports of very high temperatures (such as at Wimbledon) where temperatures in direct sunlight are given, so are not comparable with normal meteorological values.

Incidentally, in this country the Press have a wonderful time changing from Celsius in the winter time (temperatures down to MINUS 10) to Fahrenheit in the summer ( Phew what a scorcher as temperatures soar to 90 degrees).

Rainfall on this wonderful planet of ours also has a majestic annual range from basically nothing in the Atacama Desert of Chile and Peru where some places have seen no measurable rainfall for over 400 years, to nearly 12000 millimetres, or nearly 40 feet, of rain in parts of Northeast India.

In fact at Cherrapunji they get on average 11,430 millimetres of rain every year, and most of that falls in just 4 months, and would you believe there is an even wetter place just up the road from there! Some parts of Hawaii are also very wet and up in the mountains there can be as many as 350 days in the year when it rains.

Now we all know that in the northern winter there is no sunshine north of the Arctic Circle, but what about the sunniest place on Earth? Well one contender must be Yuma, Arizona in the USA which has 4055 hours of sunshine a year, or just over 11 hours every single day.

The permanent ice caps situated in the Arctic and Antarctic can produce some very strong katabatic winds which blow across the freezing wastelands. The strongest wind that has ever been recorded at low levels was at Thule in Greenland where it reached 207 miles per hour, although a wind of 318 miles an hour has been recorded near a tornado in Oklahoma in 1999, but this was at a height of 100 feet or more.

Some of the largest, and deepest, clouds that we get are formed in the tropical regions where the heated, very moist, air ascends rapidly up into the atmosphere. The largest clouds on Earth are the thunderheads, or cumulonimbus, which have been seen to reach as high as 65000 feet there, over twice the height of Mount Everest.

There has been a lot of snow this winter over the eastern side of the USA but it doesn't compare at all with the greatest snowfalls in history. In February 1959, a single snowstorm, lasting over 3 or 4 days dumped over 15 feet of snow in Mount Shasta Ski Bowl, California.

So as you can guess, although a forecaster for 30 years, I am really an observer at heart.