IT seemed most television weather forecasters were all excited by the passing of the spring equinox.

This is the point in March when the sub-solar point, where the sun is directly overhead, moves from the southern hemisphere to the north.

The actual date varies slightly but is usually on or around March 21. It’s generally regarded as being the start of spring in the northern hemisphere and the start of autumn in the southern hemisphere.

The reason we have these seasons is due to the fact that the Earth is tilted on its axis at an angle of 23 degrees off the vertical. As it stays the same all year as we orbit the sun, for six months the northern hemisphere leans towards the sun, and for the other six months the southern hemisphere is nearer - giving them the summer months at that time. Right now, it’s our turn to enjoy the weather.

It's likely that small variations in the Earth’s orbit and the angle of the tilt can create variations in climate and our weather. It’s complex because our climate varies constantly and whilst man’s impact is becoming clear, there have been significant changes in the past.

In fact, it seems the Earth’s climate has been cooling for about 50 million years, and the Antarctic Ice Sheet started to form about 34 million years ago.

It also seems we have had significant periods of ice formation from about five million years ago, when the isthmus of Panama formed and prevented the flow of tropical water to the north.

The variations between ice ages (when up to 2km of ice lay over Scotland) seem to be mainly due to small changes in the Earth’s orbit and angle of the axis. We also know inter-glacials (of which we are in one now) had warmer weather when African animals roamed Britain.

But for now we see the sun getting higher in the sky, days are longer and birds are singing, so whatever is happening in space, we can get the shorts out, here comes summer!