Yes, hard to tell how accurate the readings are. Clevedon is an idiosyncratic topography, which I won't even attempt to describe here, so I imagine that there are temperature variations even within a mile or so. Moreover, there's a lot of concrete and tarmac in the centre of Clevedon and it certainly feels warmer there than it does where I live.
Throughout the year, we in Portishead are typically a couple of degrees warmer than elevated Lulsgate, which seems to be the most 'official' of the Bristol weather stations, and that is reading 27 degrees at the moment. And we are usually a degree warmer than the 'Marty Hicks' weather station in north Bristol, which at the moment is showing 28.x degrees.
Weather data for Horfield and Filton, Bristol UK
WWW.MARTYNHICKS.UK
Current weather data from an automatic weather station since February 2004, including webcam, monthly archive, live updates. Temperature, humidity, rain, pressure, wind, solar and UV
The Clevedon station I referenced has a current observation of 29.6 degrees, so more or less in keeping with that very generalised statistic.
I don't bother taking measurements in my own garden as I once used to as it appears to have its own weird microclimate, probably because of south facing windows reflecting onto brick wall and decking that seems to have been uniquely designed to cook the soles of one's feet!