There seems to be a real competition on to produce lights with the most output. Thing is - visibility suffers most in rainy and foggy conditions and I haven't found a rear light that is actually anything more than water resistant.
Knog lights FAIL (Strobe/Beetle/Skink)
Blackburn FAIL (Click/2.0)
Cateye FAIL (Rapid 3/Rapid 5)

So who makes something actually designed for all weather commuting? Or do bicycle manufacturers think no-one has to actually drive in the rain?

Do you have fenders on your bike? I ride in all sorts of conditions, and live in a very wet climate, and have never had a problem with any taillight(ancient Vista light, Cateye TL-1000 and 1100, PBSF. Blackburn Mars 3.0, Radbot, and Dinotte 300R) getting wet and stopping working. I think this is due to the use of fenders, as without a rear fender all the water you ride through is kicked up on the taillight.

Seatstay mounting helps a lot too.

I'm an all weather rider and have never had a problem with the Planet Bike Super Flash or Super Flash Turbo while in rain, sleet, or anything else. Just make sure the batteries are good and keep on truckin.

My experience with Cateye electronics (front lights, rear lights, computers) is that if there's a problem with water intrusion, you need to pull the bike it's mounted on out of the lake and dry it out.

Four Cateye blinkies on my two commuting bikes, and no problems in any kind of weather. Including last night, when I draped bike clothes on the side of the hamper, then had to mop the floor and wash the clothes when they made a 1x3' puddle.

Planet Bike, on the other hand, I've lost one SF to water intrusion and rust, and the remaining one tends to be intermittent when the weatherman says "precipitation."

My dinotte is fine, although I haven't had any light fail due to water. I have mud guards on my bikes, and I ride in all conditions.

Try the RoadID Firefly Supernova. It claims waterproof to 300ft. I have one on order to check it out. $13 on their website.

https://www.roadid.com

You fording streams up to your waist?

my pbsf sat out in the rain all day yesterday and rode home just fine. I use fenders. I used to have one on the seat tube of my road bike. No fenders, never had a failure due to rain. And I have ridden long hours in the rain with it

Thanks for all the responses and suggestions. Regarding fenders, yup - I do have sone installed. But because of where some of these are placed, fenders probably can't help them. Anything on the seatpost under the seat would probably be safe with a rear fender, except that with a rear bag it would be blocked.

So I'm attaching these on the seat stays below the rear brakes, or or the back of a helmet, or on the back of panniers. And to test some of these for extended touring I've deliberately ridden in complete downpours for hours at a time and regularly ride 30km through snow and slush in the winter.

The usual issue is water infiltration into the battery compartment. Yeah - it can usually be dried out and recovered, but on a tour I want stuff I don't have to give a second thought to. For most people this stuff would probably be fine around town for casual use. I'm looking for something a bit more rugged - so that if I do let the bike fall over in a stream - I haven't left myself without lights. Sort of a light equivalent to studded tires for use in environmentally hostile conditions.

During the summer being wet doesn't bother me. In fact, I've taken day trips wearing a wetsuit in the rain. But the idea of having no rear lights in reduced visibility conditions bothers me. Caving lights and scuba lights have O-rings. Guess I'm looking for something similar.

I live in up in the PNW (tons of rain) and I use the Light & Motion VIS180 taillight. It's bright, has several settings and is waterproof.

Cateye LD100 is rated to 50M, sits nicely on the back of the helmet. Not sure about the newer model 110
Probably a very very reliable backup.
https://www.cateye.com/en/products/detail/SL-LD100-R/

Also grease your orings.

If I was touring, I probably would use a Dinotte plus the Supernova dyno tail light. I use the supernova plus a Radbot for randonneuring, I have ridden many miles in pouring rain and never had any problems.

I am getting some B&M dyno taillights, but I haven't had my hands on them yet, so I can't recommend them.

Thanks for the suggestion! As per the Cateye Technical Manuals, the 110 model is only water resistant and uses a pushbutton rather than a magnetic switch as an interface. No specs on output but the original 100 model looks like something I'd like to see in person. Someone here must have them for sale!

Looks like a nice light! Checked the site for specs and couldn't find any reference to water resistant or waterproof. Do you own one yourself? Thanks!

I did read the review and comments here:
https://www.bikerumor.com/2011/10/25/...is-180-review/
and again, noted a difference in the warranty period (one year as per the L&M site). Sometimes its tough to know whats what.
I do like that this light will clip to panniers as thats probably where it would be used. Battery life is short, but these wouldn't be the main lights anyway. Something like that Cateye mentioned would be OK most of the time.

Not in the same league as regular blinkies. PBK have a few LD100s left.

The Light and Motion looks particularly interesting and my only reservation is the manditory USB charging. Have also dug up some tactical headlights made by ZebraLight that can be clipped in the back of a pannier like the L&M.

https://www.zebralight.com/H51r-Red-L...lamp_p_63.html

Anyone tried these? 100 lumens is a really bright output.

I have a NiteFlux Red Zone 4. They have a video of it operating in a bucket of water, in a swimming pool - then they throw it off the end of a jetty into the ocean. It's a great light, too: bright, wide beam, several great flash patterns, several power levels even in the flashing modes, and build like a tank. A bit pricey at $100, but I think they are worth the money. Here's the video: https://www.youtube.com/watch?v=duhRwL7Yo1Q

I also have a Cygolite Hotshot. Neither it nor my previous Cateye TL-LD1100 had any problems with water, and we get lots of rain here (Victoria BC) in the winter. With the saddle above and a fender below, they are fairly well protected, of course...

My Cygolite Hotshot is often dripping wet when I take it off after a ride. It sits on the seatpost under my seatpost bag, no fenders. I just wipe it off and it keeps on ticking.

My B&M Toplight has been doing a great job for about eight years.

Paul

Put a cheap thin plastic sandwich bag over any light, pull it tight over the lens part of the light. Bunch it up on the back and put a elastic around it.
Even better is pull the bag tight, cut off any excess, carefully fold it over, and tape it with scotch tape. If you do it carefully and this is not a light that gets taken off and put back on a lot, the bag will last a long time. This works on headlights, bike computers, and cell phones. I always bag my cell phone. I pull the bag tight so the front of the phone has as few wrinkles as possible, the helps to see the buttons easily, and then fold and tape the back with any kind of tape so the back is pretty flat. You can talk and listen right through the bag. It's great to keep the phone dry in a sweaty jersey pocket.
If the bag gets ripped just replace it. The bags are almost free and weigh almost nothing.

100 lumens is not very bright. The bean pattern is important. Some flashlights that just added red lenses have a very tight beam size. That's not good for a tail light. Even with good tail lights most need to be aimed straight and horizontal to be useful. They lose a lot of visibility if they are attached to a helmet or clothing and end up facing down a little. Mounted solid to the bike and secure is important. When getting a new light don't go by ad copy to know what it looks like, put it on your bike line it up right, and walk behind your bike in the dark. Crouch down to be about where a driver would be too. Walk to the sides to get a good idea of the spread. Walk far away too.

Edit: join CandlePowerForums and read up. There are a few reviews and comparisons about the clear lens flashlight version.
Maybe the red lens version too.

Agree completely with your theory, but am a little surprised that you don't think 100 lumens is a lot for a rear light. The Exposure Flare puts out 75 and the Light & Motion Vis 180 only 35 and those two were considered the top two this year. If you have a model in particular to suggest I'd love to hear about it.

I've been through the candlepower forums. It's really not necessary to become a nember to browse the posts. Very much like BF, some of the posts are better than others. Speculation by many posters is part of the forum. The 'flashlight' I linked to is actually a tactical headlamp with a Cree XP-E red LED, beam shots have been posted and I was thinking about clipping it to the back of a pannier very much like a L&M Vis 180.

I'll probably end up buying one of each just to get some idea how easy they are to live with. User interfaces are impossible to evaluate over the Internet.

All lights I ever used wre totally watertight, never had a problem in the worst downpours.

Quick! We need names, and dates, and places! Or at least brands and models! Pretty please?