Daily temperature lag (hottest, warmest, temperatures, days)

[Ethereal]

People have made threads about seasonal lags. Now are they aware of 'daily high lag' too or is it just me?

Most of the time here, especially in summer, when we're supposed to get a high of say 35C (95F), it doesn't seem to reach that mark until like, 4:00pm and even 5:00pm. Shouldn't the hottest time of the day be at 2:00pm-3:00pm? That lagging pattern seems a bit common in Sydney.

What causes this? Is it the change of winds? Or, since how the heat is building up all day, it somehow 'climaxes' at the end of the day (when the sun is almost going DOWN)?

[Wildcat15]

It all builds up I think. Coastal cities of Florida reach the high by about 1:00pm usually in the summer, the rest of the day is kept pretty much the same by the seabreeze. I know this is an anomaly and Kentucky is similar to what you described.

[B87]

In London, the high is usually reached between 3-4pm.

[dunno what to put here]

High here is usually after 3pm. Might be different on the coast.

[Joe90]

Around 1.00 pm seems to be the peak most days, with a temperatures cooling only a little during the rest of the day.

The exception is days with Foehn conditions, which can see the peak at anytime, even sunset.

[The East Frisian]

I live on the coast and in the summer the maximum temperature on very warm or hot and sunny days is usually reached here between 4 and 6 PM. Daylight saving might play a role on this (our solar noon is around 1:30 PM on summer solstice), but perhaps also the much cooler water.

On cloudy conditions the maximum is reached somewhat earlier between 2 to 3 PM mostly.

Sea breezes that kick in in the afternoons are common until about July, not so much in August when the sea temperatures are at their warmest. On such days the maximum can be earlier like 2 PM, then the winds turns from East to Northwest and the temperature drops about 4-6 degrees (C) and mostly the wind and temperature stays that way until sunset.

[Joe90]

Originally Posted by The East Frisian

I live on the coast and in the summer the maximum temperature on very warm or hot and sunny days is usually reached here between 4 and 6 PM. Daylight saving might play a role on this (our solar noon is around 1:30 PM on summer solstice), but perhaps also the much cooler water.

On cloudy conditions the maximum is reached somewhat earlier between 2 to 3 PM mostly.

Sea breezes that kick in in the afternoons are common until about July, not so much in August when the sea temperatures are at their warmest. On such days the maximum can be earlier like 2 PM, then the winds turns from East to Northwest and the temperature drops about 4-6 degrees (C) and mostly the wind and temperature stays that way until sunset.

Interesting. One thing I've learnt on this forum, is how different sea breezes are in different places.

The sea breeze here usually starts anywhere from about 10 am until about 2 pm, but is usually in full swing by about lunchtime. The temperature will usually still rise after it has started.

The only time it sees a big drop in temperature, is if there is an offshore wind bringing warm wind, that dies off in the late afternoon (5 pm). When this happens, the sea breeze can be very strong, with thick low cloud, and is referred to as a sea breeze front.

[tenkier7]

In Fayetteville, NC
Daily low usually occurs between 6:30~7:30AM
Daily high usually occurs between 3:30~4:30PM

[Glacierx]

Originally Posted by theropod

What causes this?

It is nothing to so with buildings or wind. Think of this way. Suppose you have a bucket with 10 mm hole in the bottom. Suppose that I have a hose filling the bucket. Let's say that I adjust the pressure by the amount of energy from the sun such that at 10 am I get 10 atm of pressure. Let's also assume that solar noon is at 1:30 pm. As a result, the bucket will be filling until 5 pm even though the peak was at 1:30. After 5 pm, the bucket starts to drain. This is the same reason why it keeps getting hotter long after solar noon. It is also why the coldest time of day is after sunrise.

[bronski]

Don't think that there's any significant lag here. Solar noon is few minutes before 12 pm and highs happen between 1-2 pm. Sometimes, it even happen before noon at about 11 am. In this case at noon, thick clouds develop which prevents the temperature from going higher. At the same time, it also prevents heat from escaping which meant that the high could be sustained for a long time. Temperatures start to dip at about 4 pm.

Speaking of lows, it seem to happen just before sunrise in most places. Why is that?