Are Sleeping Bag Temperature Ratings Accurate? Discover Sleeping Bags Temperature

As a rule of thumb, it is recommended to consider the temperature rating of the sleeping bag when choosing one.This rating means that your bag will keep you warm at the lowest temperature even if you happen to be walking in the snow.But people are confused about, are sleeping bag temperature ratings accurate?

Well, It has long been debated whether sleep bag temperatures are accurate. While some experts disagree, others claim the rates are quite accurate. But, sleeping bag temperatures are affected greatly by humidity. High humidity causes the air inside a sleeping bag to be less dense, so it absorbs heat more slowly.

Here is a guide to choosing the right sleeping bag. Our discussion will cover different temperature ratings, how to interpret them, and what to look for when buying a sleeping bag.

What does sleeping bag temperature ratings mean?

A sleeping bag’s temperature rating is determined by how well it maintains air temperature, not the actual temperature outside. Typically, sleeping bags are rated between 0 and 30 degrees Fahrenheit. 

If you’ll be camping in cold weather, you’ll need a bag that is rated for lower temperatures. When camping in warmer weather, you may want to choose a bag with a higher rating.

On the other hand, A rating of 30 degrees means that the sleeping bag can handle temperatures up to 30 degrees Fahrenheit. However, if it’s colder outside, the sleeping bag will likely be much colder than 30 degrees.

So, to determine what temperature a sleeping bag can handle, manufacturers use an equation that takes into account factors like weight and insulation type. 

The equation also includes a margin of error to account for variability in weather conditions. Infact, sleeping bag temperature ratings are a way of determining how warm your sleeping bag will be when you put it on. 

However, a higher rating means the bag is warmer and will keep you more comfortable. By knowing your sleeping bag’s temperature ratings, you can plan your trip accordingly and make sure you stay warm all night long!

How do sleeping temperature ratings work?

A sleeping bag temperature rating is a measure of thermal comfort. The purpose of this is to help you choose the right sleeping bag. However, you should remember that the temperature ratings are subjective.

 Some people may prefer a warmer model than others. Therefore, you should think about the lowest temperature at which you are planning to camp.Generally speaking, the temperature ratings for sleeping bags are based on whole body heat loss models.

However, sleeping bags can differ enormously in their warmth depending on several factors.For example, your metabolism, clothing, and shelter may also play a part.

Generally speaking, the R-value of a sleeping bag indicates how warm it will be. Insulation is another important factor to consider when choosing a sleeping pad. With a warm sleeping pad, the warmest possible temperature rating may be achieved.

Infact, most people opt for a bag that has a temperature rating of at least 30 degrees Fahrenheit. While this is warmer than you may want for spring and summer, it is still not too hot. The better option for you would be a warmer model if you live in a colder climate.

Apart from that, temperature ratings are a good starting point, but do not rely on the bag to keep you warm. You can add layers to increase warmth. Also, be sure to take into account the size and weight of the bag.

Sleeping bag temperature ratings standards

When looking for a sleeping bag, it’s important to understand how the EN/ISO rating works. Although there are many factors that can affect comfort, these two standards are used to describe the temperature that an average person feels most comfortable.

What is EN rating?

The EN rating is a system used to classify sleeping bags by their cold weather performance. It uses a scale from 0 (the lowest temperature rating) to 5 (the highest). 

A bag with a rating of 3 is considered to be adequate for cool weather camping. A bag rated at 4 would be better for cold weather camping, and 5 is the best rating for severe cold weather conditions.

What is ISO rating?

An ISO rating is also available, but it is not as well known as the EN rating. The ISO rating uses a scale from 0 (the lowest temperature rating) to 10 (the highest). A bag with an ISO rating of 6 is considered to be adequate for cool weather camping. 

A bag rated at 7 would be better for cold winter conditions, and 8 is the best rating for very cold conditions.

Sleeping bag temperature ratings explained

An effective way to measure a sleeping bag’s temperature is by its temperature rating.It is a guide to the lowest temperatures at which a sleeping bag should keep an average person comfortable.

A set of new conditions were introduced by the EU in January 2005 to help regulate sleeping bag testing standards. In order to minimize performance gaps between advertised and actual standards, these standards have been developed. 

Nowadays, sleeping bags are rated by two factors:

  1. The Comfort rating
  2. The Season rating

1.The comfort ratings – how do they work?

It is possible to determine what temperature an average man or woman will feel comfortable in, what is too hot, or what is just too cold based on the comfort rating of a sleeping bag.  

Even, People don’t all have the same comfort level at different temperatures, so this instructions should only be used as a guide.

Comfort ratings are categorized into four sections! Here is the chart!

Name Features 
1.ComfortIt is possible for an average male to sleep comfortably at a temperature of up to 42 degrees Celsius without sweating excessively.
2.Upper limit Adult women can expect to have a comfortable sleep at a temperature above70F. 
3.Lower limitIt is generally advisable for an adult male to curl up at the lower limit of his comfort zone in order to sleep well.
4.Extreme limitA woman can survive at the lowest temperature at which she can be expected to survive. Sleeping in these temperatures should be considered with caution.

The seasonal ratings: How do they work?

Actually, It is important to inform buyers about the best time to use their sleeping bag based on the season. There are five levels of ratings, starting with one for summer months and going up to five for extreme cold temperatures. 

Generally, they are classified into five types-

1.Season-One A temperature of at least 5 °C at night during this time of year is ideal for this season.
2.Season- TwoAs spring and summer approaches, evening temperatures can drop to a temperature of around 0 to 5 degrees Celsius.
3.Season- ThreeIf the temperature is anywhere between 0 and -5°C on a cold night, but there is no frost on the ground.
4.Season- FourWhen using this product, it is recommended to use it during the winter months when the temperatures are as low as -10°C.
5.Season- FiveA perfect camping companion for expeditions in temperatures of up to -40°C, Ideal for expedition camping. Mountaineers usually carry these in their rucksacks as part of their hiking gear.

How to choose a sleeping bag temperature rating?

Choosing a sleeping bag with an appropriate temperature rating is essential when camping. There are many factors that go into determining the optimal temperature for you, so be sure to read up on your options before you make your purchase.

  • As you shop, don’t forget to compare the temperature ratings on competing brands. You should look for a rating that is 10 degrees Fahrenheit colder than the expected camp temperature. 
  • Also, make sure you know which season you’re planning on camping in. Season 1 is a good bet for warm nights in the summer, while season 5 is best suited for the coldest of the winter months.
  • Insulation is the most important factor to consider when looking at temperature ratings because it dictates how well the bag retains heat. A better insulation will result in a higher rating
  • However, a good quality sleeping bag is made of water resistant down, which is a byproduct of the meat industry. This isn’t as effective when it gets wet. To keep your precious pelts safe, look for a brand with a globally traceable down standard.
  • Many manufacturers have an EN standard that they must adhere to in order to sell their products which dictates what kind of fabrics on what kind of weight it can use. This also affects how warm it will be
  • In addition to the obvious, you’ll also want to take a look at the comfort rating. Generally, women have a lower body temperature than men, so they need more insulation to stay comfortable. Make sure you choose a sleeping bag that is more comfortable than one designed for men.
Choose sleeping bag with accurate temperature
Sleeping bag off pad

What to consider when choosing an sleeping bag temperature

There are several factors that go into determining the temperature rating of a sleeping bag. Depending on the body shape, sleep position, and the temperature of the environment, there may be differences. 

Furthermore, environmental factors, such as body hydration, affect the user’s comfort. A few things should be kept in mind when evaluating sleeping bag temperature ratings, however.

Rating procedure

The first is that not all sleeping bags are rated the same way. While the ratings on the tags usually correspond to the lowest temperature rating, some manufacturers may actually produce lower-temperature bags than their competitors. 

This means that even if you have a temperature rating of 30 degrees Fahrenheit, you might be able to get cold if you’re using a 25-degree bag from another company.

Choose the right temperature

When going camping, you should choose a sleeping bag temperature that is appropriate to the expected weather. It is recommended that you use sleeping bags that have a lower limit temperature when it is extremely hot during the day (over 70°F).

 And vice versa – if the daytime temperature is expected to be cold (below 45°F), you should use a sleeping bag with a higher limit temperature.


 As you choose your sleeping bag, you should consider the type of climate in which you will have to use it. In terms of climate, there are three types:

  • Cold,
  •  Moderate
  •  and warm.

Sleeping bags are made for different climates, so you need to choose the one that is best for your needs.

Body type and weight

The other thing to consider is your body type and weight. Sleeping bags aren’t just for people who are cold – they can also help protect people who are overweight or have a large build.

 If you’re not sure what weight range your sleeping bag should be rated for, ask the manufacturer what size person their bag should be used by.

Well fitted

Make sure your sleeping bag is appropriately fitted before buying it. A good way to do this is to measure your body length and width and compare them to the dimensions listed on the product packaging or online reviews.

If you’re between sizes, go for the larger one – but don’t overdo it! You shouldn’t have any trouble squeezing into a smaller size if necessary, but if it’s really tight then your insulation won’t be as effective as it could be.

Test accurately

Finally, always test a sleeping bag in advance – even if you think you know what temperature rating it has. Different temperatures will cause different levels of warmth inside the bag

Once you have considered all these factors, you can start to look at the different sleeping bags that are available. There are a lot of different brands and models to choose from, so you need to find the one that is best for you.

How sleeping bag warmth tested

To determine how warm a sleeping bag is, manufacturers typically test it at a temperature around 30 degrees Fahrenheit. However, this temperature can be misleading because it’s often too cold for humans to sleep comfortably.

However, testing the warmth of a sleeping bag is an important step in determining whether it is suitable for the conditions in which you plan to use it. 

Here is a step-by-step guide for testing the warmth of a sleeping bag:


Fill a large garbage bag with insulation materials, such as old clothes or blankets. Make sure that the bag is roughly the same shape and size as your body.

Step- 2

Lie down inside the garbage bag and zip it up, leaving only your head exposed.


Get into your sleeping bag, making sure that it is fully zipped up and that there are no gaps between your body and the bag.

Step- 4

Lie in the sleeping bag for several minutes to get a sense of how warm you feel. Pay attention to how your feet, hands, and head feel, as these are the parts of the body that are most susceptible to cold.

Step- 5

Take note of the temperature of the room or area where you are testing the sleeping bag. This will give you a baseline for comparison when you test other sleeping bags.

Step- 6

Repeat steps 1-5 with different insulation materials in the garbage bag to get a sense of how the sleeping bag performs in different temperatures.

Step- 7

Additionally, if you have a way to measure temperature inside the bag, you can also measure temp to get a more accurate reading.

Step- 8

Once you have completed the testing process, compare the results to the temperature rating of the sleeping bag. This will give you an idea of how well the bag will perform in different temperatures.

By following this guide, you’ll be able to get a good sense of how warm a sleeping bag is, and whether it is suitable for the conditions in which you plan to use it.

Are All Sleeping Bag Temperature Ratings Tested The Same?

Most sleeping bags are rated in degrees Fahrenheit, but what about the summer months when the temperature can range from the high seventies to the low nineties? 

To find out if all sleeping bag temperature ratings are accurate, we tested seven different bags under three different conditions: indoors at 65 degrees, outdoors at 90 degrees, and outdoors at 105 degrees.

Each bag was tested twice in each condition with an average of the results used for review. The results showed that all of the bags were within three degrees of each other, which is pretty much what you would expect based on how these ratings are calculated.

 In fact, the only exception was the Super Elephant Bag at 105 degrees where it was four degrees off from being accurate. This could be because this bag is made specifically for extreme temperatures and may not be as forgiving when it comes to inaccuracy.

Sleeping bags temperature tested
Sleeping Bag Temperature Rating

Temperature rating are not set in stone

Usually, Sleeping bag temperature ratings are not set in stone. While manufacturers typically provide a range of temperature ratings for their products, these ratings can vary considerably depending on the particular sleeping bag model and how it was tested.

In fact, some reviewers have found that sleeping bags rated at 30 degrees Fahrenheit may actually heat up to 50 degrees Fahrenheit during use due to variations in individual body heat production.

Moreover, to account for these variations, sleepers should take into account both the specific conditions they’ll be camping in (e.g., whether it will be cold or warm outside) and the sleeping bag they’re using.

For instance, if you’re going to camp in cold weather where the temperature drops below freezing at night, an ultra-lightweight sleeping bag that is rated for 25 degrees Fahrenheit might not be warm enough.

 Conversely, if you’re camping in a warmer climate where the temperature inside your tent reaches 70 degrees Fahrenheit at night, a heavier sleeping bag rated for 35 degrees Fahrenheit may be too hot.

Why Do Women’s Sleeping Bags Have Comfort Rating

Almost every woman has experienced the horror of a sleeping bag that is too hot or too cold, and many have resorted to stuffing their heads through the neck opening to regulate their body temperature.

 Infact, sleeping bag temperature ratings can be misleading, as they are based on laboratory testing conditions that may not be representative of the real world. Women’s sleeping bags typically have lower heat ratings than men’s bags because women generally weigh less and have smaller bodies.

 Even if a woman weighs 150 pounds and is in the same weight category as a man, his sleeping bag may still be rated at 30 degrees while hers may only be rated at 20 degrees.

Additionally, women often sleep on their side which increases their chances of getting cold since they tend to get more exposure to air on their chest and sides.


What is a good temperature rating for a sleeping bag?

A good temperature rating for a sleeping bag depends on the expected weather conditions. In general, a rating of 30°F (-1°C) is suitable for summer camping, while a rating of 0°F (-18°C) or lower is needed for winter camping.

Can you use a 20 degree sleeping bag in the winter?

It depends on the specific winter conditions. A 20-degree sleeping bag may be sufficient for winter camping in mild or moderate conditions, but it may not provide enough warmth for extreme cold. It’s important to consider the temperature rating, insulation type, and other factors when choosing a sleeping bag for winter camping.

How often should I replace my sleeping bag?

The lifespan of a sleeping bag depends on the frequency of use, quality of care, and type of insulation. In general, a well-maintained sleeping bag can last for 5-10 years. However, if it shows signs of wear and tear, loss of loft, or reduced warmth, it may be time to replace it.


One important thing to take into consideration when buying a sleeping bag is the temperature rating. In this article, we tried to point out about are sleeping bag temperature ratings accurate? If you still have any confusion,please read again carefully.

However, it is important to remember that these ratings are based on the average user and may not be applicable to you depending on your body type or sleep  style. So, It’s always best to test a sleeping bag before use in order to get an accurate reading for your specific body temperature needs.

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David Stone
David Stone

I'm David Stone - world traveler and award winning travel writer and photographer. I can help you plan any trip, anywhere, for any amount of time...without the frustration of a bad itinerary.

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