Cold temperature: Causes peripheral vasoconstriction and central vasodilation

• Increased central blood volume --> Lower ADH due to increased blood volume through kidneys
• Increased central blood volme --> leads to atrial stretching, increased preload --> Increased ANP release

The increased peripheral vasoconstriction due to the body's attempt at heat conservation causes more blood to be shunted to central organs. The more blood that ends up in your central organs (heart, brain, other viscera) causes distention of the the central blood vessels, mainly the heart (remember the heart is actually just one giant blood vessel). When the heart experiences an increase in volume it secretes ANP and BNP, which promote natriuresis by dilating the afferent arteriole. The resulting loss of sodium decreases serum osmolarity and your body compensates by decreasing ADH. This is why you tend to pee in a cold pool.