High sensitivity weather station from DIDCOT was used locally for climatically parameters measurements, during last-two years, starting May 1st 1995 to June 30, 1997. Two different type of photovoltaic cells were belt-on to the set-up for current-voltage measurements, during the same period of time. The results confirms the known solar cells effects due to seasonal variation and global solar radiation changes. The effects of Infrared intensity on the silicon solar cell efficiency was shown. There is a good agreement between measured global solar radiation and efficiency of photovoltaic cells. The effects of dry temperature during the time period on the cells were shown.