Wednesday, 9 February 2011

The Sun Rising in the South

At least, that's more true than to say it rises in the east, as we always used to be told.

It was yesterday, 8th February, about 7:20am and had been getting light from about 6:00. The sun is rising at 160 degrees, making it 20 degrees north of south and 70 degrees south of east.

14 days before, the sun had risen some 3 to 4 degrees further south.

At the north pole, of course the annual sunrise and sunset are both due south. Where I live in Młochów the latitude is 52.06°. This is roughly equal to Stevenage, well down in the southern half of England and between Calgary and Edmonton in Canada, making it completely north of mainland USA (assuming that excludes Alaska).

Just up the road, Warsaw's climate is humid continental. The average temperature is −3°C in January and 19.3°C in July. January, the coldest month, has an average minimum temperature of -6.1°, whilst July has an average high of 23.8°. Record extremes are -30.7° and +36.4°.

Stevenage has an oceanic climate with an average monthly temperature ranging from +4.5°C (January and February) to +17.5°C (August). January has an average minimum temperature of +2°, whilst August has an average high of +23°C. English record temperatures are −26.1° (close to Stevenage) and +38.5° (further south).

The colder winter temperatures here are no surprise, but I also felt that the summer days here were much hotter than the 0.8° difference suggests. Warsaw's June to August daily maximum is some 1.5° hotter, whilst Stevenage's nights are 2.5° colder.

Edmonton has a relatively dry humid continental climate. Average daily temperatures ranging from −11.7°C in January to 17.5°C in July. January has an average minimum temperature of -16°, whilst July has an average high of 22.8°. Official city record temperatures are −40° and +38.3°, although a minimum of −49.4° is recorded in 1886.

Precipitation level differences are also remarkable. Warsaw's annual 495mm compares with Stevenage's 532mm and Edmonton's 477mm. However, despite the English reputation for wet summers, Warsaw's June to August 66mm level compares with 45mm in Stevenage. This, again, wasn't something I had expected. England does regularly have dry summers and we do have wet ones, but the balance here didn't seem to be right. It's probably just my memory, of course, but I suspect that the regularity with which hot Polish summers are broken for short periods by torrential downpours compares with more regular, low intensity rain in England. If you're thinking of summering in Edmonton, however, its June to August average is 83mm.


Michael Dembinski said...

Nice post Steve! At last a scientific approach to the question of Warsaw vs. England weather. Do you have hours of sunshine per year for Stevenage? Yesterday's Gazeta Stołeczna said that Warsaw enjoyed 2,200 hours of sunshine in 2010. How would Edmonton compare?

The July/August comparison is interesting; July is Poland's wettest year. May and June are generally much finer in Warsaw than in England - can you prove/disprove this assertion?

The contrast between the two sunrises just two weeks apart is amazing!

Pan Steeva said...

Stevenage had between 1570 and 1660 hours of sunshine in 2010 according to regional data from the Met Office. However longer term averages give between 1440 to 1540 hours for the Stevenage area compared with Warsaw's 1571.

I think this Met Office page will prove you right about May and June as well, looking at the Stevenage area compared with Warsaw in Wikipedia.

Pan Steeva said...

However, according to a Polish Meteorological Institute map, Warsaw only had between 1,600 and 1,650 hours of sunshine in 2010.

Edmonton beats all of this, with an annual average of 2,299 hours of sunshine (from Wikipedia).

I was once told that Busko Zdrój's micro-climate gave it the most sunshine in Poland, which was why it was a good spa resort to visit. (Most visitors are/were National Health Fund financed rest and recuperation visitors.) Sad to say, although Polish Wikipedia records that it has a very large number of hours of sunshine, whilst the English version claims: "we have plenty of sunny days", they are only said to have 1,151 hours of sunshine. The figure should really be 1551.

No guarantee for any of my figures, either.