Weather its hot or not

[2complicated]

Can somebody please explain in simple terms why one day can be hotter than another? For the last two days, the sun has been in the same place (?), no cloud, and Wednesday was breezier where I live, and yet it was significantly hotter than Tuesday. If it is to do with stored heat in the atmosphere or the ground, why dont equatorial countries keep getting hotter and hotter every day? What is it that determines the days temperature?

[heathfield]

The temperature of the air arriving over Britain plays a large part in how hot it feels. Recently, air from the Mediterranian has been moving over Britain. It's already warm to start with, and though it cools as it moves north, the sun heats it further. If we had air moving down from the Arctic Circle, it could be just as sunny , but the days would feel distinctly cooler.
Humidity has a lot to do with it too. Moisture in the air can act as an insulator, keeping cool air cool despite full sunshine, and warm air warm, giving us those hot muggy nights. Air moving up from the Azores tends to be moist, while air coming in from the Continent tends to be drier.
If the air is very dry, the sun will feel much more intense during the day, but at night the heat escapes into space. This is how some deserts can experience incredibly high daytime temperatures, yet be frosty at night.
The heat in the tropics is regulated by air movement. The hot moist air rises, and moves away toward the poles - the heat is taken with it.
So the day's temperature is determined by 1) the sun's position, (High in summer = more direct and hot, low in winter = less direct and cooler). 2) Where the air over Britain is coming from, (warm or cool, and moist or dry)

[gen2]

It is the balance between energy in and energy out. If more energy arrives than leaves, then it will get hotter.

Heat may arrive in the following ways:
Direct solar radiation - the colour of the ground will determine how much is absorbed (albedo)
Heat may be transported from a hotter region by marine currents. eg Gulf Stream / North Atlantic Drift.
Heat may be transported from a hotter region by moving air masses.

Heat may be lost in the following ways.
Heat may radiate back out into space. More so with cloudless skies - clouds act as a blanket
Heat may be transported away by moving air masses.
Heated air may rise by convection to be replaced by cooler descending air.
Heat may be used up evaporating water.


I've probably missed a few minor points but those are the main ones.

[2complicated]

Two great simple answers. Thank you

[matt66]

One minor point is the power of suggestion. if the weather man says it is going to be a scorcher then we think it is a scorcher. TV news bombard us with this info on an hourly basis and we are conditioned to think it is true.