Does Temperature Affect Ring Size?
If a ring fits in the morning and feels tight by the evening, nothing is wrong with the ring. Your fingers change size throughout the day.
Quick answer
Yes. Heat makes blood vessels expand and fingers swell by up to half a size; cold shrinks them by a similar amount. Measure at room temperature in the late afternoon.
Why it happens
In warm conditions your body widens the blood vessels near the skin to release heat, so soft tissue in the fingers swells. In the cold the opposite happens and blood is drawn towards the core, so fingers narrow.
Exercise, salty food, alcohol, flights and some medications produce the same swelling effect.
When to measure
- Late afternoon or early evening, at normal room temperature.
- Not straight after a shower, a workout or a long flight.
- Not on a very cold morning or a very hot day.
- Three times, on different days, then take the average.
Living with the swing
Choose a size that is comfortable at your average, not your smallest. A ring should slide over the knuckle with a little resistance and not spin freely at the base. If summer makes it tight, a slightly domed or comfort-fit band will help.
Frequently asked questions
How much do fingers swell in heat?
Commonly a quarter to a half ring size, which is 0.2 to 0.4 mm of inside diameter.
Should I size up if I live somewhere hot?
Measure locally at your normal daytime temperature rather than adding a size arbitrarily. If you are between sizes, take the larger.
Keep reading
For an expensive ring, confirm the size with a jeweller before ordering — see the ring size FAQs for resizing advice.