Aside from the effect of cold temperatures on the human body, it's also important to consider the effect of cold temperatures on the virus.

One study found reduced virus infectivity at 37 degrees celcius while it was stable at 6 and 23 degrees.

And while we're at it, there's even more data on the flu. Quite a few studies found that "cold temperatures and low relative humidity are favorable to the spread of influenza virus."

So humidity is also important, as well as the interaction between humidity and temperature:

there seems to be some general indication that minimal survival for both lipid-enveloped [e.g. influenza] and non-lipid-enveloped viruses [e.g. rhinoviruses] occurs at an intermediate RH [relative humidity] of 40–70% (Arundel et al. 1986). Also, it is important to note that temperature and RH will always interact to affect the survival of airborne viruses in aerosols.

In short, being cold doesn't seem to make a difference to you, but it does make a difference to the virus. They prefer colder (less humid) environments. This does mean you're more likely to catch a cold when it's cold, because the virus is more likely to survive and be transmitted.

Aside from the effect of cold temperatures on the human body, it's also important to consider the effect of cold temperatures on the virus.

One study found reduced virus infectivity at 37 degrees celcius while it was stable at 6 and 23 degrees.

And while we're at it, there's even more data on the flu. Quite a few studies found that "cold temperatures and low relative humidity are favorable to the spread of influenza virus."

So humidity is also important, as well as the interaction between humidity and temperature:

there seems to be some general indication that minimal survival for both lipid-enveloped [e.g. influenza] and non-lipid-enveloped viruses [e.g. rhinoviruses] occurs at an intermediate RH [relative humidity] of 40–70% (Arundel et al. 1986). Also, it is important to note that temperature and RH will always interact to affect the survival of airborne viruses in aerosols.

[Edit: In my initial answer I suggested that being cold doesn't make a difference to you. That's not quite true. It does seem to increase susceptibility to infection, though of course the point is that you do need to be exposed to a virus; you don't get a cold just from being cold.]

While temperature may have an effect on your susceptibility to infection, it also has an effect on the survival of the virus outside your body. They prefer colder (less humid) environments. This does mean you're more likely to catch a cold when it's cold, because the virus is more likely to survive and be transmitted.

Aside from the effect of cold temperatures on the human body, it's also important to consider the effect of cold temperatures on the virus.

One study found reduced virus infectivity at 37 degrees celcius while it was stable at 6 and 23 degrees.

And while we're at it, there's even more data on the flu. Quite a few studies found that "cold temperatures and low relative humidity are favorable to the spread of influenza virus."

So humidity is also important, as well as the interaction between humidity and temperature:

there seems to be some general indication that minimal survival for both lipid-enveloped [e.g. influenza] and non-lipid-enveloped viruses [e.g. rhinoviruses] occurs at an intermediate RH [relative humidity] of 40–70% (Arundel et al. 1986). Also, it is important to note that temperature and RH will always interact to affect the survival of airborne viruses in aerosols.

In short, being cold doesn't seem to make a difference to you, but it does make a difference to the virus. They prefer colder (less humid) environments. This does mean you're more likely to catch a cold when it's cold, but only because the virus is more likely to survive and be transmitted.

Aside from the effect of cold temperatures on the human body, it's also important to consider the effect of cold temperatures on the virus.

One study found reduced virus infectivity at 37 degrees celcius while it was stable at 6 and 23 degrees.

And while we're at it, there's even more data on the flu. Quite a few studies found that "cold temperatures and low relative humidity are favorable to the spread of influenza virus."

So humidity is also important, as well as the interaction between humidity and temperature:

there seems to be some general indication that minimal survival for both lipid-enveloped [e.g. influenza] and non-lipid-enveloped viruses [e.g. rhinoviruses] occurs at an intermediate RH [relative humidity] of 40–70% (Arundel et al. 1986). Also, it is important to note that temperature and RH will always interact to affect the survival of airborne viruses in aerosols.

In short, being cold doesn't seem to make a difference to you, but it does make a difference to the virus. They prefer colder (less humid) environments. This does mean you're more likely to catch a cold when it's cold, because the virus is more likely to survive and be transmitted.