Many schools now have automatic weather recording stations.
Data on temperature, humidity, pressure, rainfall, wind direction and speed can be downloaded hourly, daily and monthly. Files can be save in CSV format and then displayed, graphed and analysed eg using Excel. Schools are exchanging data and experiences. In Oxford we are very fortunate to have access to the Radcliffe Observatory which has a long and continuous record of local weather. Ddata can be entered onto a spreadhseet package such as Excel or Claris Works eg to calculate yearly averages for particular figures.