I was wondering if anyone knew the weight of the Sierra Designs Isotope rain jacket? I thought I read it was reported to be under 5 ounces...but cannot confirm that anywhere. Looking to get the lightest rain jacket out there right now and any help is appreciated.

I got one for a present. Men's size large weighed just 4.5 oz!!! However, it failed a quick, 5-min shower test miserably. My hair was completely wet (worthless hood) and my tee shirt was completely soaked through on the shoulders and the front. The back side fared better -- it was "only damp". If I were out in the cold, the soaking would be more than enough to cause hypothermia. I purposely kept the test short to make sure that perspiration wouldn't be a factor.

I complained to SD, mailed the loser back to them, and got a brand new replacement. I could feel the thicker PU coating immediately. This jacket weighed 5.5 oz or a whole ounce more. But hey, it would still be worth it if it's truly waterproof, right?

The replacement jacket still failed -- although it performed better than the first one. This time, the hood kept out the water, and my tee shirt was only damp rather than soaking wet. However, the two pockets (zipped up tightly) still let in enough water to form two water balloons!

Verdict: Ignore the seductive siren calls. Save your money or just buy any one of those UL water resistant wind jackets. They are cheaper, they are much more breathable than the Isotope, and they provide just as much rain resistance as the Isotope. Alternatively, take a look at wp/b jackets in the 7-8 oz range: GoLite Virga or TNF DIAD. No direct experience with either, but surely they can't be as bad as the SD Isotope! Shame on SD for both marketing hype and shoddy product in this instance!

Edited by ben2world on 10/16/2006 15:31:45 MDT.

Size large weighs almost 6 oz on my scale. A couple of warnings about the Isotope: some of the seams aren't sealed (although I assume that a regular seam sealant could fix that); breathability sucks.

As far as I can tell, the fabric is effectively waterproof. That's based on high-pressure spraying, not field experience. Perhaps mine is the newer version that Benjamin got as a replacement.

I wouldn't recommend the Isotope jacket, but if you're interested I do have an unused (with tags) size large that I would be willing to sell. I also saw a very cheap ($20 or $30) used XL at the Seattle REI the other day.

Thanks for the great feedback! I definitely need something that breathes. While weight is a critical factor...waterproof and breathable are key. I have to be able to wear it while chugging up a hill!

I saw an outdoor research goretex that looked enticing. I may wait and see if anything pops out this winter/spring for the new season.

Breathability? OK only for walking downhill at a leisurely pace in cool weather.

Waterproofness? None at any speed.

Just returned this jacket to REI yesterday, after using on a mildly wet weekend trip. Jacket had wet out after 20 minutes on the trail also tape came loose from all seams and making it a tangled mess to try and wear again without removing it completely. Waiting for Golite Virga to arrive within the next few days, seems like a much better option.

I got one at REI for $30 a few weeks back.

I used it this past weekend for about an hour in the rain and it held up fine. Needs more testing, but I live in Washington, and that won't be a problem from here until November.

It comes it at 5.3 oz for a mens large on my scale and I've noticed it isn't as breathable as one would like.