Bangkok flooding with hot humid air

Yesterday Bangkok smothered in humidity. Long slog of the hot season arrives.

Invented in Thailand: world's best tropical hat

World's greatest hat for hot weather. Perfect shade and ventilation. Additional bonus factor: the layered structure of the hat provides an extra R value of about 0.5, so that significant temperature drop occurs between the outside and inside of the hat. Example: today with an air temp of 30, the outside of the hat had a temp of 38 (from solar heating) and the inside surface was 33. Would addition of a little foil on the underside of the hat improve things?

Invented in Thailand: world's best tropical hat

World's greatest hat for hot weather. Perfect shade and ventilation. Additional bonus factor: the layered structure of the hat provides an extra R value of about 0.5, so that significant temperature drop occurs between the outside and inside of the hat. Example: today with an air temp of 30, the outside of the hat had a temp of 38 (from solar heating) and the inside surface was 33. Would addition of a little foil on the underside of the hat improve things?

Everyone smiles here -- even in the heat!

Today we visit our village neighbors near our Korat farm. A hot  afternoon – temp 35°C (95 F) – and we find them sleeping in hammocks underneath their house. Can they be comfortable? Well they look and act comfortable and according to my CBE Berkeley thermal comfort calculator (you can google this great tool) the average person, dressed very lightly as they are, sedentary or sleeping, with surrounding surfaces at less than 30 deg C (86 F) and with a floor fan turned to medium, should be happy with a temperature of 32 to 34° (91 F). But the saving fact is that the ground temperature, because of its high thermal mass, is only 29 C (84 F) and they are enjoying radiant cooling from underneath their hammocks, which according to the ASHRAE-based tool, put them right smack in the middle of the comfort zone -- with no aircon. We don't need to bring in any race-based factors to explain this("these people are used to it") to reach this conclusion. But we do have to permit a certain afternoon laziness; everything is quiet in the village at this time of day.

Bangkok woman turns on table fan

One night earlier this week at 9 PM a Thai woman (wearing a cotton nightgown and viewing a Thai soap opera on her ipad in bed) turned on the table fan in the bedroom, for the first time in weeks following a winter cold snap with temps often below 20 C (68 F). She had aircon available but did not choose this option, preferring the fan. The temperature at this signal event was 26 C (79 F) and humidity 60%. 

Research in Thailand done several years ago determined that this is exactly the temperature where Thai people prefer at least a little stir of air movement; in general studies have found that locals, both men and women, like air velocities between .5 and 1 m/s when the temperature moves much above 26 C (79 F). These breezy levels of air movement have traditionally been consigned to the word "drafts" in Western culture. 

Words do more than convey information; they transform it, sometimes in surprising ways. Sati ("mindfulness") becomes sloth. Kit mahk ("thinking a lot") becomes depression. When as I often do, say in Thai to a taxi driver it is cool today, I mean pleasantly so. He will reply with an agreeable shiver, taking my expression of satisfaction as an expression of disatisfaction. 

But not a complaint. Or, O my Buddha, not an opinion. For more on why elders should not hold opinions, read the sample of my forthcoming book which you can download for free by clicking to the right.

Bangkok man reports feeling chilly at 79 degrees F

The cool weather continues, average daily temps at Don Muang are about 21-22 degrees C. I've been feeling cold at 26 C (79 F) degrees room interior temp for three days now.

Is my perception abnormal?

I checked by the wonderful ASHRAE thermal comfort calculator at CBE Berkeley this morning and entered my conditions: boxer shorts (clo=.18), relaxed (met=.8), no fan.

Here in this psychometric chart (much more on this important tool later) my environment (blue dot) is much cooler than the yellow comfort zone, the temperature would have to be in the low nineties for me to be happy, according to ASHRAE standards. Conversely, we can say that most people dressed as lightly as I am, will be most comfortable with the temp around 95 F, or 35 C.

Twenty thousand days at Don Muang

This graphic shows the average daily temp at Don Muang since 1951 (top to bottom). Courtesy of the Thai Meteorology Department. 

Values to left are dips in temp, values to right are hot days. The year markers (white horizontal lines) are set to Songram which as expected is close to the hottest day of the year.

For larger size of this graphic click on "20,000 days in Bangkok" in right sidebar. 

I have several ideas about this record.

1. Bangkok weather is more variable annually than I once expected. Perhaps this is true of Thai people too.

2. There is a very sight rising trend to temps at DM, maybe a degree over the whole sixty three year period. Urban heat island effect (heat-gathering effect of urban development) is certainly part of the reason for this, perhaps the full reason. Hence significant global warming is not apparent in this record.

3. Some apparent changes can probably be explained by the re-siting of the measurement point or changes in immediate surroundings including construction.

4. The small gap at the bottom is due to absence of records during 2011 flooding. The record stops mid 2013, I will add more later.