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During 2018 the intensity and its variation in time were monitored, every hour the presence of radon gas in two distinct points near each other in São José dos Campos, Brazil. One point was situated 25 meters high (ACA tower) and the other 3 meters high (ITA laboratory). Two identical RadonEye RD200 (ionization chamber) detectors were used calibrated in picoCurie/liter (pCi/l) or Bequerel/cubic meters (Bq / m3). These measurements indicate that there is always a (day/night) variation in the intensity of the local radon gas presence. With dry and hot periods, there is increasing in radon gas intensity. Intense rains during short period of time, there is also increasing in presence of the radon gas in that site. Fine and continuous rains provoke decrease in the presence of radon gas measured in the place. Comparisons between radon gas intensities per hour with gamma and neutron changes between (0-10) MeV of energy at the same time interval were observed.