Layering is not complicated. It’s the process of adding and removing layers of clothing to keep your body comfortable in changing weather and temperature conditions.

Billions of dollars have been spent trying to optimize this process (and sell you stuff), but it’s really very simple: Put clothing on when you’re cold, take clothing off when you’re hot. Which clothing? That’s the rub, as they say. But don’t worry. We’ll walk you through what each layer is, how to layer, and when you’ll want it. Once you’re done here, check out our guides to the Best Base Layers, Best Puffer Jackets, Best Merino Wool, and Best Rain Jackets for more.

Updated February 2026: We’ve updated our advice based on new experiences, and put in a few new picks culled from all the gear we’ve tested in the last year.

Layering Basics

The key to layering is knowing what the layers are for and when to add and remove them. The high level overview looks like this:

• Base layer: The layer that touches your skin. These provide some warmth, but they’re primarily important for wicking sweat away from your skin. Being damp means being cold.
• Mid layer: The layer that’s—wait for it—in the middle. This is the layer where you actually start insulating, or trapping body heat. This is the key to the whole system and should usually be more than one layer (e.g., a lightweight fleece and a puffer jacket).
• Outer layer: The top layer is the waterproof, windproof layer that makes sure that nature does not steal all that precious heat you’ve retained in the mid layer. This is sometimes referred to as a “shell.”

While you won’t always be wearing all of these, especially when you’re exerting yourself while walking, running, et cetera, it’s usually worth carrying all three. If it’s cold, you can start with all three on and peel them off as you get warmer. When it’s hot you can do the opposite, pulling out a shell when you stop on a windy ridge. Obviously there are situations where you don’t need to carry all of them. Hiking the Florida trail in July? Skip the mid layer, ya lunatic.

Base Layers

SmartWool

Merino Classic Long-Sleeve

Let’s start with underwear. Whether boxers, briefs, boxer briefs, or bras, go for materials that are going to help move moisture away from your skin. I have found merino wool to be ideal for underwear, but it’s worth trying different fabrics to find which works best for you.

Next comes what we generally think of as base layers: relatively tight-fitting but not overly restrictive pants and shirt with the dual purpose of insulating in cold weather and wicking sweat in hot. Again, there is a wide array of fabrics. If you opt for merino wool here, you benefit from wool’s natural ability to smooth out temperature variation across your skin, keeping you more evenly warm/cool (I call this temperature modulation).

There are also other options for fabric here, which includes Nuyarn. It has much of the benefits of merino (it’s usually more than half merino) but adds some nylon to provide extra strength and durability, as well as speeding up drying times. The latter can be important in very wet climates. In my experience, synthetic base layers do not perform as well at either insulation or moisture removal, though they will often dry faster, last longer, and are often cheaper.

Telefónica has announced that its strategy to transform network processes through automation and artificial intelligence (AI) has “far exceeded” initial expectations.

The Madrid-based global comms provider’s Autonomous Network Journey (ANJ) programme was launched in 2021, and is based on the Autonomous Networks framework defined by the TM Forum, which aims to provide a systematic method for operators from AN strategy planning to implementation, and guide operators to carry out AN work more efficiently.

For Telefónica, network autonomy is conceived as a path that advances from fully manual environments to fully autonomous networks, classified in levels 0 to 5. At their highest levels, networks are capable of self-learning, span multiple domains, and possess self-configuration, self-optimisation and self-healing capabilities. This is said to ensure “the highest levels” of efficiency and reliability.

Telefónica recurrently measures the evolution of autonomy in each principal network domain – fixed access, mobile access, transport, IP, core and telco cloud – as well as in what it calls a number of key processes such as planning, testing, deployment and operations. In November 2025, the operator revealed a roadmap to reach an average level of autonomy of 3.75 by 2028, and reach level 4 by 2030.

The resulting weighted indicator reflects the actual maturity of each of the operations in the countries in which it operates, and shows how each country is progressing towards more predictive, efficient and self-sufficient operating models. The group’s global level consolidates the progress of the operations in a standardised way, offering a unified view of Telefónica’s progress towards autonomous maturity.

Telefónica says it finished 2025 with a total of 12 Level 4 use cases, a category it says already reflects a “very advanced” level in the development of autonomous networks and thus accelerates its transformation process. Level 4 use cases are defined as those capable of acting autonomously based on the intention transmitted by a human and are essential to raise the global average of autonomy.

In addition, it noted that what seemed to be a long-term journey to reach its objectives has accelerated significantly thanks to the strong commitment of the operations teams of Telefónica Spain, O2 Germany and Vivo (Brazil). And thanks to the joint effort of the three operators, Telefónica closed 2025 with 12 Level 4 use cases, all of them fully operational. Among these is the autonomous creation of network capacity with Vivo’s AI (Fractal), and the operator is also deploying autonomous detection and resolution on Vivo’s virtualised 5G Core and autonomous creation of client fibre capacity (Fractal II).

It is also creating a digital twin for the transport network (NetOptimizer) from O2 Germany and Intelligent planning for the O2 Germany transmission network. The Germany subsidiary is also deploying automation for operations analytics, ticketing and diagnostics though a virtual assistant, and automation is part of an in-service software change of Core 5G (InService Software Upgrade).

An Intelligent multi-domain correlation at the customer level is offering proactive and automated detection of impact, anomalies and root cause in 4G/5G at O2 Germany.

Work in Spain encompasses autonomous detection and resolution of weaknesses in Telefónica España’s IP network and Telefónica Spain’s intelligent planning for the deployment of customer fibre (Smart Capex). Other projects include NetCheck for error-free software changes and intelligent configuration of Telefónica España’s IP network.

Overall, Telefónica regards the achievement of 12 Level 4 use cases as consolidating the group’s position as a European benchmark in network automation and demonstrating that “the combination of technology, talent and focus is the right way to move towards an autonomous network”.

Usually, when you see a feel-good story about finding a lost dog, you don’t immediately react with fear and revulsion. But that was indeed the case in response to a Super Bowl commercial from Amazon-owned security camera company Ring. There’s now a group offering to dole out a $10,000 bounty to wrest back control of the user data Ring controls.

The ad showed off a new feature from Ring called Search Party. It uses a network of Ring cameras to scour a neighborhood for signs of lost dogs. But as the details of a leaked internal Ring email reported by 404 Media revealed, the service could eventually be used to find other animals and people as well.

The commercial was met largely with widespread criticism across social media and the tech press, which called out Search Party for essentially being a thinly-veiled neighborhood surveillance dragnet. People are even publicly destroying their Ring cameras. In response, Ring immediately canceled its partnership with the controversial AI surveillance company Flock. Ring CEO Jamie Siminoff has been on something of an apology tour since the Super Bowl commercial aired. (A Ring spokesperson acknowledged our request for comment and says the company will provide one shortly; we’ll update this story when we hear back.)

The Fulu Foundation, a group founded by repair advocate and YouTuber Louis Rossmann, pays out bounties to people who can remove user-hostile features on connected devices. The nonprofit saw this pushback as a moment of opportunity for people to take back control of their devices.

“It’s been an interesting moment for people to grasp exactly the trade-off that they have had to accept when they installed these security doorbell cameras,” says Fulu cofounder Kevin O’Reilly. “People who install security cameras are looking for more security, not less. At the end of the day, control is at the heart of security. If we don’t control our data, we don’t control our devices.”

Fulu’s latest bounty is for Ring’s video doorbell cameras, meant to encourage hackers and tinkerers to disable software features that require the devices to send data to Amazon. The reward is a potential payout of $10,000 or more.

To score the bounty, the winner will have to adhere to a few requirements designed to make sure the hardware itself stays in working order. After modifications, the device must be able to work with a local PC or server, and be capable of halting data sent to Amazon servers or requiring a connection to other Amazon hardware. All of this must be done without disabling on-device hardware features like motion detecting and color night vision. The job also has to be accomplishable with “readily available and inexpensive tooling” and “instructions that a moderately technical user could carry out” in less than an hour.

“This needs to be a weekend project,” O’Reilly says, “where someone who was creeped out by a commercial and wants to take back control can take care of it, get it done, and be able to sleep soundly at night knowing that they’re the only ones who can see their footage.”

The first person to accomplish all of that with a Ring camera—and prove they can do it—gets the money. The reward starts at $10,000, but will likely grow as donors contribute more money (it’s already sitting closer to $11,000 as of publication). On top of that, Fulu will award up to an additional $10,000 to match donations for the winner.