The magnets shown here will not only add that extra weight your shower curtain needs, but they can obviously also magnetically stick your shower curtain to your bathtub.
1. Popular method
2. Magnets hold each other in place (place one on either side of the curtain)
3. Also sticks liners to tubs
Click here to view on Amazon
These particular magnets have been used in order to stop clinging and billowing, with one reviewer stating 'bought these to weigh down a shower curtain, worked like a charm'. I guess it goes without saying, but if you're having a brain fade moment and you're wondering how these are attached, it's as simple as placing one on each side of the curtain. You also need to space them in such a way that they don't all stick together when you're opening/closing the curtain, so place them at different heights. These magnets are very powerful for their size. They could be positioned on the bottom of your liner or positioned further up depending on what works best for you.
They are also going to be great for those who have metal tubs, as they also magnetically secure the bottom of your curtain to your tub.
Clip On Shower Curtain Weights
1. Adds 6.4 ounces
2. Pack of 4
3. Marketed as tablecloth weights
Click here to view on Amazon
If you'd rather clip on some weights, you could also consider a product like these ceramic weights pictured above. Each of these clip on weights is 1.6 ounces. They're sold in a pack of 4, meaning it'll give your shower curtain an extra 6.4 ounces. Perhaps the heading above this picture is a little misleading because they're actually sold as table cloth weights, but they'll clip onto a shower curtain just fine. They're described as decorative, as they have an aged ceramic blue and white scroll design. If you're checking these out on Amazon, take a look at the items that others bought or viewed, and you'll find a reasonable variety to choose from. Only issue is they may make "clanking" noises on the side of tubs.
Need something heavier?
Recommended Reading - Using tablecloth weights on shower curtains
If you're obese, your enormous mass may be creating a gravitational pull which is sucking in your shower curtain.
I'm obviously totally kidding. However, perhaps losing a few inches off your waist might make you a little less vulnerable.
There's several theories, with the most accepted being the Bernoulli's principle, which states that air pressure is decreased by an increase in velocity, which occurs due to the flowing of water. Basically, the air movement caused by the flow of the water causes a difference between the air pressure inside and outside. This is actually increased when there is no gap between the floor and the bottom of the liner. Therefore, creating a gap may allow you to minimize the effect.
Other theories focus on the simple fact that heat rises, which results in cooler air being sucked upwards. Whether it's vortexes, air pressure or condensation, it seems likely that there are several factors at play. Or perhaps the problem is that all air feels entitled to the same conditions. The cold air outside the shower feels ostracized, demeaned and shut out, whilst the privileged hot air boastfully puffs itself up in a display of excess and privilege. Your curtain's blowing around and billowing is simply a manifestation of our consumerist capitalist society.
What are your best options?
The magnets pictured above appear to be quite a popular option, whether for holding it firmly up against your tub, or adding some weight. However, there's actually a variety of products and ideas for stopping shower curtains from blowing inwards. Check out my blog post 5 ways to stop your shower curtain blowing in for a few more ideas.