Summer solstice at a time of pandemic

Covid lockdown was announced in Poland towards the end of astronomical winter, a fortnight into meteorological spring. On 16 March, the first working day of lockdown, the sun set at 17:42, less than three-quarters of an hour after my laptop lid went down. I'd return from my 90-minute long walk in the dark. Lockdown was a depressing, worrying moment, but at least spring was coming. The days were getting longer, warmer, brighter, and the clocks would soon be going forward, giving that welcome extra hour of daylight in the evenings.

Three months on, the pandemic is still very much with us, but the year has reached its zenith. From tomorrow, the days will start to get shorter - imperceptibly at first, but accelerating as we approach the autumn equinox. Then in late-October the clocks go back, and then the Hammer of Darkness comes down. All of us who experience seasonal affective disorder fear those dismal November days in the Northern Hemisphere as daylight is squeezed out little by little, leaving Warsaw with a mere seven hours and 42 minutes at the winter solstice. This year, it is likely that those days of dread will be accompanied by a second, possibly more deadly, wave of Covid-19.

But for the time being, make hay while the sun shines - even if it's not shining! Last week saw the spread-rate of Covid-19 in Poland fall to its lowest since the pandemic began.

Out into the countryside, then. Darkness falls late, the blending of day into night takes longer than in winter.

After yesterday's storms, the land was still warm long after sunset, the clouds interesting.

What do 'noon' and 'midnight' mean to us today? Since the late 19th century, electric light has brightened city nights; today all network-connected devices show exactly the same time, expressed as 'UTC'. To this (also known as Greenwich Mean Time), one adds or subtracts hours dependent on longitude and adjusts for daylight length (summer time). 

Historically, however, 'noon' had a specific meaning - it was that moment when the sun was exactly at its zenith, when (in the northern hemisphere), your shadow would point due north. Depending on what latitude you stood, noon occurred at a slightly different time. Noon occurred in London eight minutes before the sun reached that same angle in Bristol - a problem for the early railways, quickly solved by the introduction of 'railway time', facilitated by the telegraph.

Warsaw is 20 degrees east of London. One hour is 15 degrees of longitude (360 degrees of the globe divided by 24 hours of the day). Warsaw is one time zone east of London, so accounting for that, the sun rises, reaches its zenith, and sets in Warsaw around 20 minutes earlier than on London clocks. (That 'around' takes into account the Earth's wobble.)

Now, midday - noon - is literally the middle of the day. The meridian. Equidistant from sunrise and sunset - but take the summer time adjustment into account.

Today is the summer solstice; the sun will be directly over the Tropic of Cancer at 21:43 today, the northernmost line of latitude upon the sun's rays fall at exactly 90 degrees. 

Here in Warsaw, the sun rose at 04:14 and will set at 21:00. Noon in Warsaw - the zenith of the sun's travel from horizon to horizon - is at 12:37 (11:37 if not for the summer time shift). Eight hours and 23 minutes after sunrise, eight hours and 23 minutes before sunset.

Midnight is analogous to midday. For us modern folk, 'midnight' does not seem particularly late; I try to be in bed before 11pm, but when I'm writing or editing photos, bedtime is often past midnight. Yet midnight literally means the middle of the night! It is halfway between sunset and sunrise! For pre-electricity humans, the biological clock was more in tune with the sun. Once the sun had gone down, how long you'd stay awake for depended on how many candles you could afford to burn. Without clocks and the artificial construct of 'summer time', sunrise in mid-summer in Warsaw would be at quarter past three am. That's when one would wake, break fast and begin work in the fields.

Below: orchard under glowering skies.

The weather is typical for high summer. Convection storms build up throughout the day as the sun's rays cause condensation of moisture on the ground. Water vapour rises into the atmosphere consolidating into clouds that hour by hour grow ever higher; once they have the mass and the height to reach altitudes where the air is colder, the vapour turns into rain - often heavy. Watching the weather-radar maps on Meteo.pl, I often see the Vistula acting as a corridor along which storms build and move north-westward. Today will be rainy, but warm.

This time five years:

Ahead of the storm

This time seven years ago:
Fashionable bicycles for Warsaw's hipsters

This time eighte years ago:
On Jarosław Gowin and leadership in Polish politics

This time nine years ago:
Death of a Polish pilot

This time ten years ago:
Doesn't anyone want to recycle my rubbish?

This time 11 years ago:
End of the school year

This time 12 years ago:
Midsummer scenes, Jeziorki