A waterproof jacket has two jobs: keep rain out and let the moisture from your body escape. How well it does each is shown by two numbers on the label, the hydrostatic head and the breathability rating. The rest comes down to features such as the hood, the seams and the cut.
For a day standing on a riverbank or walking in Irish weather, a jacket with at least 10,000 mm hydrostatic head, taped seams and a hood that moves with your head will cover most situations. If you are out in heavy rain for hours, carry a rucksack or fish from a boat, look higher.
Fit matters as much as fabric. Try the jacket over the layers you would actually wear, lift your arms as if casting and check the sleeves still cover your wrists.
What the numbers mean
Hydrostatic head
Hydrostatic head (HH) is measured in millimetres. It is the height of a column of water the fabric can hold back before water is forced through. The higher the number, the more pressure the fabric resists. Pressure rises where a rucksack strap presses on your shoulders or where you kneel or sit on wet ground.
Outdoor brand Alpkit suggests a minimum of 10,000 mm for most activities and at least 20,000 mm for proper all-weather use. Many budget jackets quote lower figures or none at all, which is fine for short showers but not for a full day in steady rain.
Breathability
Breathability is usually given in grams of water vapour per square metre over 24 hours (g/m²/24h). A higher figure means more sweat can escape. As a rough guide from Alpkit:
| Breathability | Suits |
|---|---|
| Around 8,000 g/m²/24h | Low effort: standing, sitting, short walks |
| 10,000 to 15,000 g/m²/24h | Most walking where you will warm up |
| 20,000 g/m²/24h and above | Hard effort such as fast hill walking |
Brands use different test methods, so treat these figures as a guide within one brand rather than a precise comparison between brands. An angler who spends most of the day standing still needs less breathability than a walker climbing a hill, but more insulation underneath.
Features worth looking for
- Taped or sealed seams. Every stitch hole is a way in for water. Fully taped seams are standard on proper waterproofs; “showerproof” or “water resistant” jackets often skip them.
- A hood that fits. Look for a stiffened peak and adjusters at the back and sides so the hood turns with your head. A hood that blocks your view is a problem when you are watching a float or a line.
- Storm flap or water resistant zip. A flap over the main zip, or a coated zip, stops rain driving through.
- Adjustable cuffs and hem. Velcro cuffs keep water from running up your sleeves when you reach forward. A drawcord hem keeps wind out.
- Pockets above a waist belt or wader top. Chest or high hand pockets stay reachable and dry when you wear waders or a rucksack.
- Length. A longer cut covers your seat when you sit on a bank or a wet seat. A shorter jacket suits wading and moves better on a walk.
Jacket types compared
| Type | Good for | Watch out for |
|---|---|---|
| Lightweight packaway | Carrying just in case, summer showers | Thin fabric, little warmth, often lower ratings |
| Waterproof shell | All year with layers underneath | No insulation of its own |
| Insulated waterproof | Cold, still days on the bank | Can be too warm when walking |
| 3 in 1 | Flexibility: shell and inner fleece or jacket that zip together | Heavier, and both parts must fit well |
You can compare all of these in the men’s waterproof jackets and women’s waterproof jackets ranges. A packaway jacket is a sensible spare to keep in a tackle bag or car, even if you own a heavier main coat.
Getting the fit right
- Size for your layers. Try the jacket over a fleece or the thickest layer you plan to wear. If it only fits over a T-shirt, it is too small for an Irish winter.
- Check your reach. Raise both arms and reach forward. The hem should not ride up above your waist and the cuffs should still cover your wrists.
- Check the hood with the zip done up. The collar should cover your chin without pressing on your face.
- Mind the label. Some jackets are cut as men’s or women’s and some are unisex. Product names are not always consistent, so check the size chart on the shop’s page rather than relying on the title.
The men’s range and women’s range also list wellies, which are the other half of staying dry; see choosing wellington boots.
Keeping it waterproof
Most new jackets have a durable water repellent (DWR) finish that makes rain bead and roll off. When that finish wears off, the outer fabric soaks through (“wets out”). The jacket may still keep rain out, but it stops breathing, so you get damp from sweat on the inside and assume it leaks. Alpkit describes a failed DWR as the most common cause of a jacket feeling wet inside, and says the fix is usually a wash and reproofing, not a new jacket.
Dirt, sun cream and body oils speed this up. Washing with a technical cleaner rather than ordinary detergent, then reproofing, brings most jackets back. The washing and reproofing guide explains how.
Quick checklist
- At least 10,000 mm hydrostatic head for regular use, more for all-day rain.
- Breathability that suits how active you are.
- Fully taped seams and a covered or coated main zip.
- A hood that adjusts and turns with your head.
- Adjustable cuffs and hem.
- Room for a fleece underneath, checked with arms raised.
- Care label read before the first wash.
Common questions
Is “water resistant” the same as waterproof?
No. Water resistant or showerproof fabric will shed light rain for a while but is not designed to keep out sustained rain, and the seams are often not taped. For a full day outdoors in Ireland, choose a jacket sold as waterproof with a stated rating.
Why do I get wet inside a waterproof jacket?
Usually it is condensation from sweat, not a leak. It happens most when the outer fabric has wetted out, when you work hard in a jacket with low breathability, or when the air is cold and damp. Open the vents or front zip when you walk and reproof the jacket when water stops beading.
Do I need waterproof trousers as well?
If you sit or kneel on wet ground or walk through long wet grass, yes. Water runs off the jacket onto your legs, and wet jeans get cold fast. Waterproof overtrousers pack small and pair well with wellington boots.
