The hottest time of the day

Well, yada yada yada, and that's about it.

I think there's always a lag effect after the peak sunshine.

Like, the sun heats up surfaces (streets, sidewalks, roofs, etc.) which retain heat, and everything gets cumulatively hotter until the sun gets less intense.

Something like that.

Hot enough for ya?

I don't know, but, while I see the highest temperatures in late afternood, that's also the time when it starts feeling comfortable. Maybe better breezes, maybe the sun at a lower angle, or maybe just longer shadows. Anyway, June 21, or thereabouts is the longest day, but July and August tend to be a taddie bit warmer.

sozobe wrote:

I think there's always a lag effect after the peak sunshine.

Like, the sun heats up surfaces (streets, sidewalks, roofs, etc.) which retain heat, and everything gets cumulatively hotter until the sun gets less intense.

Something like that.

Hmmm, interesting answer. The temperatures that are posted are from our official Environment Canada weather outfit, which locally, would be measured at our airport.

The temperatures for all day are recored on their website and one can follow the progression. Typically, the hottest time seems to peak at 5 to 6pm.

I'm sure on an official temperature reading apparatus, wouldn't they be mounted away from hot surfaces? Not sure on that, but thanks for your perspective.

but it's hot enough for me when it gets past 25 degrees Celsius (77 F).

The ground itself cools overnight and begins heating back up during the day. The sun reaches it's peak strength at about 2pm and lasts for an hour or two so the ground (and buildings, etc...) will heat to that temp. Until the point where the ground has reached it's max temp for the day the ground is actually absorbing heat. Once it has recahed it's max temp for the day it is releasing heat.

For the remaining part of the afternoon you have the combination of the direct heating of the sun and the radiated heat coming off of the ground. The two combined release more heat into the ambient air than the direct heat of the sun alone so the hottest part of the day will be shortly after the most intense direct heating from the sun.

Since temps are typically taken within a few feet of the ground itself the ground temp is more important than the direct heat from the sun (all "offical" temps readings are "in the shade" readings. If you go to the airport you'll fined their eqipment enclosed in a box to prevent direct sunlight from reaching them.).

The hottest time of the day is later in the afternoon. The sun heats the Earth which, in turn, heats the lower troposphere. The incoming solar radiation starts each day at zero at sunrise, reaches a maximum at noon and falls back to zero at sunset. The warm earth also radiates out into space and continues to do this at night. If you plot the incoming solar radiation on a graph together with the outgoing terrestrial radiation, you will see that the two lines cross twice, once a couple of minutes after sunrise when the coldest part of the day occurs and it crosses again in the afternoon, usually between 3pm and 4pm, when the hottest part of the day occurs. While incoming solar radiation is greater than the outgoing terrestrial radiation, the temperature rises. When the terrestrial radiation is greater than the solar radiation, the temperature falls.

Quote:

but it's hot enough for me when it gets past 25 degrees Celsius (77 F).

PFFfffThhththt. Don't come here then.