if its been running hot then this is normal, given the weather you would have had to be thrashing it.
on the other hand Lykaios makes a good point about DPF regeneration.
whats your typical journey and when was last time the car had a good long run?
if you don't know what regeneration is:
diesels now have a DPF (diesel particulate filter) these work by having in effect a blocked filter except for microscopic holes which air can pass but not diesel particulates.
the particulates build up in the filter, until the filter Is up to full operating termperature, at which point the particulates breakdown/burn off.
if you don't get the filter up to temperature often enough then the filter can become clogged and the car will alter the cycle to artificially increase the temperature in the exhaust and filter. some say they can feel the engine running a bit roughly when this happens.