Are you confused when listening to the weather reports on the 1st day of June to hear the weather forecaster inform you it is the first day of summer followed some 3 weeks later to be told that Summer has arrived with the occurrence of the Summer Solstice. The majority of people associate the change of the seasons with the solstices and equinoxes not with the meteorological seasons so what is going on?
Meteorological Seasons
The meteorological seasons are split to make it easier for meteorological observing and forecasting to compare seasonal and monthly statistics. So Meteorological summer will always run from June 1st to August 31st. Thus, the meteorological seasons are made of 3 monthly seasons:
Summer: 1st June – 31st August
Autumn: 1st September – 30th November
Winter: 1st December – 28th/29th February
Spring: 1st March – 31st May
Solstices and Equinoxes
The dates of the two solstices and two equinoxes are not fixed and can vary due to the Earth’s orbit of being approximately 365.25 days each year. This year’s dates are:
Spring Equinox: 20th March
Summer Solstice: 21st June
Autumn Equinox: 23rd September
Winter Solstice: 21st December
Do we need 2 dates for the change of seasons?
The meteorologists want their dates purely for the purpose of statistics, The Astronomer uses the dates for measuring the position of the Earth in relation to the Sun. This year we have had temperatures approaching 20º in March followed by snow in early April. However; the seasons continue to change but these do not occur overnight, so does it really matter if we have 2 dates?
Diary
Summer Solstice: 10.13am Tuesday 21st June (The longest day)
Meteorite Showers: May 5th/6th The Eta Aquarids created by debris from Comet Halley. These can be observed between the east and south east in the early hours around 02.30 – 04.00 hours.
Mercury can be observed during the first 10 days of May at Sunset, but cannot be seen again during the following weeks leading up to July.
Venus Almost hides low down in the eastern sky during May but can be seen very close to Jupiter (what is known as a conjunction) on the 1st May. Will be difficult to observe during the lighter months of June.
Mars can be observed during the pre-dawn sky looking towards the eastern horizon; close to Jupiter between 26th May and 3rd June.
Jupiter As described above Jupiter has pre-dawn encounters with both Venus and Mars and continues to rise higher in the eastern/south eastern sky during June.
Saturn Starts to rise during the second week of May towards the south east in the pre-dawn sky and continues its rise in the sky throughout both months of May and June.
John Harris