Corny, but . . .
. . . the old wives' tale of corns hurting before a change in the weather is true. Feet, and in fact pretty much all of the body, tends to swell a bit when the barometric pressure drops. The more precipitous the drop, the more one notices. It is most noticeable with the feet, as they are incased in shoes that won't give. Hence the pressure on the corns against the inside of the shoe.
Never heard about warm weather alone having that effect, though. However, warm air is slightly less dense than cold and might exert a tad less pressure on the surface of the body.