Here in New Zealand, there is always a lot of talk about when the seasons actually change.  Should they occur around the 21^st of March, June, September and December?  Or on the 1^st of those months?

In the US, where the season changes are observed around the 21^st of March, June, September and December there is not as much controversy.  But there is still some mystery to it.  Meteorologists in the US refer to the 1^st of March, June, September and December as the beginning of the “meteorological season”.

American meteorologists use whole months to identify seasons (meteorological seasons). In the northern hemisphere:

• Meteorological spring takes place during March, April, and May

• Meteorological summer takes place during June, July, and August

• Meteorological autumn takes place during September, October, and November

• Meteorological winter takes place during December, January, and February

Of course, here on this side of the equator the seasons are reversed.

An Astronomical seasonal change bases the season on the date of the corresponding equinox or solstice.

In other words, astronomical seasons change on the days the Earth is tilted closest or furthest from the sun (solstices), and those on which the sun is directly over the equator (equinoxes). In the northern hemisphere:

• Astronomical spring begins on the spring equinox

• Astronomical summer begins on the summer solstice

• Astronomical autumn begins on the autumnal equinox

• Astronomical winter begins on the winter solstice

So which is better?  That question will probably never be answered.  There are pluses and minuses to both methods.  In addition, those on both sides of the controversy can be very passionate about what qualifies as the start of a particular season.

But one thing is for sure, New Zealand isn’t the only country that wonders if there isn’t a better way to keep track of the seasons.

Homepage/  David Hawke

-By Howard Joseph, WeatherWatch.co.nz