One option that strikes a reasonable balance between cost and
reliability would be a basic Davis Wizard III weather station
plus
data logger and PC link. This does provide an outside
temperature
sensor in addition to wind speed/direction, but is primarily
intended
for measuring wind data. Total cost is around the £400 mark
inc VAT.

Thank you for the suggestion. However I fear that we cannot
afford that level of expenditure at the moment.

Are there any cheaper options around?

Anne