Changes in the Weather

It is not ideal to place the vivarium in direct sunlight, as obviously this will have an effect on the temperatures in the vivarium.  On very hot days in the summer you may find you have difficulty in keeping the cool end temperature down to 85 degrees.  If this is a particular problem for you you can buy small fans which attach inside the vivarium and help keep the air circulating.  This is another benefit of having a permanent digital thermometer displayed as you can see the effect the outside temperature is having. 

Temperatures at night

Bearded dragons need a good temperature drop at night in order for them to switch off and go into a good sleep.  In their natural habitat the temperature will drop quite severely.  Bearded dragons can happily stand nighttime temperatures of 60 degrees fahrenheit (16 centigrade) when adults, or 65 when babies (18 centigrade).  Most vivariums will therefore need no night time heat at all.  If you do want night time heat DO NOT use a heat mat - beardies can burn their stomachs if they lay on these as they cannot feel heat through their stomachs.  Instead you could use a ceramic heater that doesn't let out any light.

In many cases on very cold nights simply covering the vivarium with a thick blanket will keep it sufficiently warm.

How does a Thermostat work?

The thermostat control sits outside the vivarium, and normally has a probe attached to it which is placed inside.  The thermostat controls the heat lamp, switching it on and off to maintain the correct temparature in the vivarium - much like a central heating controller in your house.

There are two types of thermostats - which one you use depends on the type of heating bulb you are using.  A Dimming Thermostat works by reducing the power gradually, but doesn't turn it off completely.  These are used with light bulbs as they don't keep switching the bulb on and off, and therefore prolong it's life.  The gradual dimming down and brightening up makes it a more natural constant light for your bearded dragon.

The Pulse Thermostat sends power in pulses - they are used with ceramic bulbs which don't emit light.  A normal light bulb would flash if it was using with this type of thermostat.

My Bearded Dragons Header Banner
MyBeardedDragons website contains information for the new owner on how to keep a bearded dragon properly so that it is happy and healthy.  An active forum dedicated to bearded dragons gives advice and support to new and experienced owners. 

Contact Michael
Please Visit the Sitemap to see all my Information Pages about Bearded Dragons
Join us on
Back to Top

Temperature and Thermostats

Why is the temperature of the Vivarium so important?
It's common knowledge that a bearded dragon's vivarium needs to be heated, but sometimes people are not aware of how important the temperatures are, and how to make sure that the vivarium is kept at the right temparature, and doesn't get too warm.

Keeping the right temperature in your bearded dragon vivarium is vital to its health and well being.

The temperature of the basking spot should be 105 degrees fahrenheit (40 degrees centigrade).  This does not mean that one end of the vivarium should be this warm, just the temperature directly under the basking light.  You can raise the temperature at the basking spot by raising where the bearded dragon will bask by placing a rock, bricks or log directly under the light.

What is the correct temperature?

Equally as important as having a hot place to bask, bearded dragons need to have a cool area where they can go to cool off.  Being cold blooded animals bearded dragons control their internal temperatures by moving between hotter and cooler areas.  Not being able to cool down adequately is just as bad as not having a warm enough place to bask.

Vivariums are therefore set up so that one end has the basking spot, and the other is cool.  The cool end should be no more than 85 degrees fahrenheit (29 degrees centigrade).

As maintaining the correct temperatures is vital to the health and well being of a bearded dragon you cannot rely on a heat lamp alone and will need to have a thermostat to control the temparature range. e

Using a Thermostat

A thermostat should be considered is an essential piece of safety equipment rather than a control.  It shouldn't be thought of as something to try and keep the basking area hot, but to keep the cool end at the right temperature for the bearded dragon to retreat to when it gets too warm.  (You might notice that the temps on most thermostats only go up to about 92 degrees fahrenheit).  A common mistake is to put the probe at the hot end of the vivarium, and then wonder why the basking spot isn't reaching temperature!

The aim of the thermostat is therefore to keep the cool end no warmer than 85 degrees.  Once this is understood it's easy to understand that the probe of the thermostat should therefore be at the cool end of the vivarium.

Michael Recommends:
I recommend Habistat thermostats.  I've used both the dimming and pulse stats for some years now without any problems! 

Measuring the Temperature

Many pet shops stock cheap stick on dial type thermometers.  Unfortunately these are not accurate enough to ensure the health of your bearded dragon.  The ideal way to measure the temperature is to have a digital thermometer - and the best of all is one with dual inputs.  This allows you to measure the temperature at the cool end and at the basking spot at the same time.  The thermometer stays in the vivarium meaning you can always see in one glance that you are maintaining the environment exactly right. 

Setting the Thermostat

Setting the right heat setting on the thermostat to make sure you are maintaining the correct temperatures is a matter of trial and error.  This is the main reason why it's usually advised to set up your vivarium about a week before bringing home a new bearded dragon so that you can be sure you have the temperatures right before introducing a new pet to his new home. 

Start by putting the probe at the cool end.  Check the temperature at the cool end, and at the basking spot.  Make sure the probe is on or only just above the floor of the vivarium - it's the temperature where the beardie is that is important - not six inches above his head!  Remember, if the cool end is about right, but the basking spot is not warm enough, you can try and raise the basking spot so the bearded dragon will bask closer to the light, or you can lower the light towards the place where he will bask. 

If the cool end is too cool, move the probe further along the viv.  You will need to leave it a couple of hours for the temperatures to stabilise each time you move the probe, so be patient.  You may need to do this over a couple of days.  Eventually you will find the right spot, and your temperatures will be spot on. 

What wattage basking bulb should I use?

It is interesting to understand that a 100 watt bulb which is dimmed to 40 watts is actually less bright than a 60 watt bulb dimmed to 40 watts.  Although there is nothing wrong with using a ceramic bulb which emits no light at all and many bearded dragons bask quite happily below them, reptiles are attracted to bright light to bask so anything that mimics sunlight is more natural for them.  A 60 watt bulb should be more than adequate in a vivarium up to 4 foot in length.  If you use a 100 watt bulb it won't end up being so bright.


Heat needs to escape from the vivarium otherwise once the cool end is 85 degrees the basking bulb will dim and stay dimmed, and the basking spot will only reach the same temperature as the cool end.  Most vivariums are supplied with vents in the back so that heat is lost and doesn't build up.  If you are really having trouble keeping the basking spot temp up without overheating the cool end it might be an idea to try another couple of vents.

Advanced ideas

We are keeping bearded dragons in captivity in a very limited environment.  There are things you can do to mimic more naturally the temperature changes they would experience in the wild. 

You can buy time-variable thermostats that adjust the temperature depending on the time of day. These are expensive, but could be used for some wonderful setups. If you are using a large vivarium you could consider having 2-3 of them, each linked to their own lightbulb (with their own basking spot). Put the 2-3 probes together to create one permanant cool end.  Set one stat to come on first thing, set to 85 fahreheit. Set the other(s) to 70 fahrenheit first thing. This will give you one basking spot for the morning. Set the first stat to switch down to 70 fahreheit at lunchtime, and the second stat to switch up to 85 fahrenheit. Your basking spot will move, representing the movement of the sun across the sky (in nature, reptiles have to move during the day to track the sun and the best basking spots). If you have a third thermostat, do the same, but with it coming on in the late afternoon. It may be a solution to all of the lazy bearded dragons that are only too happy to sit around by their light and not move for an entire day...