Not much Blazing in changeable June


Barley field on sunny June evening, near Bury Lane (photo: Ian Apps)

Not much ‘Blazing’ in changeable June

"Blazing June" didn't live up to its billing, but it well and truly broke the drought, and proved to be a month of contrasts, with strong sunshine and warm days followed by thunderstorms and then cool, windy and wet, before the cycle repeated again.

The most dramatic weather came close to Midsummer’s Day, and it’s no surprise that with bright sunny weather and the sun at its highest in the midday sky the UV index hit 8.3, which is as high as it is likely to get at these latitudes. We cannot be sure of Epping records, but nationally UV levels were widely at record levels, so it is likely to be a local record as well. With that also came the highest temperatures of the year so far: 30.4°C on 25th, during a short period of four days of heat over 28°C. This short spell also brought some uncomfortably warm nights, with temperature overnight from 24th to 25th no lower than 17.3°C. 

Despite the changeable weather, overall the mean temperature was 16.6°C, which places this June fourth warmest of the 36 years on record. That means this year to date we've seen our warmest January, 4th warmest February, an above average March, 3rd warmest April, equal warmest May, and now our fourth warmest June. It's hard not to conclude that global warming is having a strong effect on Epping weather.

Earlier in the month, a dramatic spell of wet thundery weather produced 40mm of rain over two days, with the wettest day on 18th giving 30mm, well over an inch of rain. Overall, the month has been wetter than average, welcome after a run of dry months, with 77.6mm, or 137% of the long term average for June. Overall, it rained on 15 days in June, often in the form of heavy showers or thunderstorms.

With a warm month, it is no surprise that the wind direction has spent almost the whole  month south of the east-west axis, especially between south and west. It has often been quite breezy for June, with Beaufort force 4 recorded on ten days in the month.

 

Graph of maximum and minimum daily temperatures recorded in June 2020

Bar chart of daily rainfall accumulations for June 2020

Below is the summary data for June 2020.

MeasureUnitMinimumAverageMaximumAverage minAverage maxTotal
Absolute humidityg/kg4.28.315.1
Relative humidity%3472.197
Temperature°C5.916.330.411.621.6
Wind source°4187359
Wind direction°0178359
Wind strengthmph03.017
Rain daily accumulationmm02.630.077.6
Barometric pressuremm995.11013.61026.8
Solar irradiancehPa0200.51165
UV indexW/m²01.48.6
Cloud base altitudem657052000
Dew point°C0.810.720.1
Heat index1625.245
Wind chill°C5.616.733

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