Summer 1975: From Ice to Fire

Doing Summer 1975 today which was quite an interesting Summer. It was also one of the best of the 20th century. However, a lot of people tend to forget about this season because it was followed by the granddaddy of hot Summers in 1976. Summer 1975 was excellent and it's sad how forgotten it tends to be.

Using the Summer Index for Armagh Observatory, June 1975 was the 10th best month from 1880 to 1979.

I have generated this graph of Irish stations' daily maximum temperatures for Summer 1975 using Met Éireann's historical data and as you can see, plenty of 20°C+ days. Going by the peaks in temperature, you can see that there were multiple warm spells or interludes through the season after a very cool start to June in the first 3-4 days with maximum temperatures widely of only 11-13°C. In early August, temperatures surpassed 30°C in parts. Three stations that did so were Kilkenny, Carlow (Oak Park) and Casement Aerodrome which had maximums of 30.5°C, 31.0°C and 30.5°C respectively on August 3rd. Ballybrittas, Co. Laois recorded a maximum of 31.5°C on the same day which had set a new August record for Ireland and this would be later equalled at Carlow (Oak Park) on August 2nd 1995, 20 years later.

June was a very dry month with it being the driest June since 1942 and for some, the driest on record. The period May 14 to June 30 1975 was almost completely dry for parts of the midlands and east with barely any rainfall. Lots of sunshine and warm days in the latter part of June combined with the ongoing drought gave rise to high rates of evapotranspiration and this led to a serious depletion of soil moisture. Growth of crops were poor as a consequence.

The month's IMT would be much higher if it were not for the cool nights at times under the light winds and clear skies. Birr's overnight temperature of -0.3°C on the 1st June was the lowest for June since 1962. At this same time, snow took place over localised parts of Ireland but it was much more impactful over the UK especially on the 2nd.

Braemar, Scotland had a maximum temperature of just 6.6°C on the 2nd with an overnight minimum of -3.3°C at Gleneagles, Scotland. The grass minimum got down to -5.0°C at Balmoral, Scotland. At Edinburgh, the maximum was 9.8°C. The daily CET for the 2nd June 1975 was 8.1°C which was the coldest June day since 1816. The daily CET for the 31st May was even colder at 7.1°C which in that year was the coldest day since the 10th April. -5.1°C was the minimum at Carnwath on May 31st which was a new record for that date.

From UK Met Office:

Southern counties of England had a mainly dry night with clear spells. Elsewhere, it was a cloud night with outbreaks of rain, sleet or snow. Clearer weather with showers quickly pushed into western Scotland after midnight and spread south and eastwards into parts of Northern Ireland and northwest England by dawn. Showers affected many northern and western areas of Scotland and Northern Ireland during the morning. At the same time a band of rain, with some sleet or snow in places, across the Midlands quickly pushed south to lie across southern counties of England by midday. Eastern Scotland continued to see a good deal of cloud and wet weather and this slowly pushed south into parts of northeast England during the morning. The afternoon saw the cloud and rain, with some sleet or snow in places, across southern England clear away into the English Channel. Much of the country then had a mixture of sunshine and showers, some of the showers were wintry in nature with sleet and snow especially across northern areas but not exclusively so. Snow showers were reported as far south as the London area. Eastern Scotland and northeast England had a wet afternoon with rain, sleet and occasional snow at times which continued well into the evening. Elsewhere, the showers slowly turned lighter and more scattered during the evening with most places dry by midnight. Winds were light to moderate across eastern England but a fresh to strong northerly wind affected many western areas of the United Kingdom

It was a cold day for the beginning of June everywhere with temperatures well below the seasonable average.

Sleet and snow were reported in East Anglia and the Midlands and even penetrated as far south as the London area. This was the first time since 1888 that snow and sleet had been reported as widely so far south during the summer. Several county cricket matches were abandoned due to snow, the most notable were between Essex and Kent at Castle Park, Colchester and between Derbyshire and Lancashire at Buxton. Strong to gale force winds, occasionally severe on coasts, occurred in Scotland and Northern Ireland with many places reporting gusts in excess of 40 knots.

Here's some pictures of the snow on June 2nd 1975.

This was an exceptional event in June 1975! It has a return period of around 250 years much like the Great Storm of October 1987. Remember this fun fact I told you that showed just how exceptional the cold was for the time of year and the snow:

If it weren't for the first 4 days of June 1975, the Summer CET would be 17.3°C instead of 16.9°C. The season stands as the 13th warmest Summer on record with 16.9°C but if it were 17.3°C, it would be the 5th warmest Summer on record. Must be the warmest Summer on record to have snow falling during it!

By the weekend following the snow and cold, it turned much warmer! In fact, temperatures widely got into the 20s with some getting up to 25-27°C. Highest temperatures I can find in Ireland from June 6th-11th:

There was a cooler interlude from the 14th-18th when there was some rain in parts especially out to the west though as I already said, some of the midlands and east had barely any rain from May 14 to June 30 1975. It became warmer again afterwards and this continued into July with places in the midlands had over two consecutive weeks of each day successfully reaching at least 20°C.

July 1975 was a rather more unsettled month generally especially to the south though this was mostly down to a violent thunderstorm that struck on the 10th down there. The midlands and east continued to be exceptionally dry. Birr had its driest May to July period on record. Sunshine was average for July. There was a cooler spell between the 20th and 25th when maximum temperatures went down to the mid teens compared to the high teens and low 20s which much of July brought, in gusty northwesterly winds.

August was another dry and warm month. It got off to a hot start with the temperatures I've named above and on my graph, you can definitely see them by the large peak at the beginning of August. The month again produced many days of at least 20°C for stations but there were also some short cool spells to compensate. It was the warmest August since 1955 and the driest since 1947. Sunshine tended to be on the more variable side with the north and west being duller than average but the east was very sunny.

Summer 1975 had a lot in it, snow, heat including 30°C, blue skies, thunderstorms, drought. Think it would be a favoured season among weather enthusiasts especially in this day and age.

Monthly sunshine totals (hours) for Irish stations for May to August 1975:

*May 1975 was Scotland's sunniest month on record with 329 hours being recorded at Tiree this month. Belmullet's sunshine total of 289.6 hours during May 1975 made it Ireland's sunniest May on record.

Remember that the June 1975 snow was preceded by the exceptionally mild Winter and the cold October of 1974. October 1974 was colder than December.