A system for determining a distribution in a greenhouse of values of an environmental parameter, the system comprising one or more air flow sensors for measuring a magnitude and/or direction of air flow at first one or more positions in the greenhouse, and one or more environmental sensors for measuring the values of the environmental parameter at second one or more positions in the greenhouse, and a data processing system that is configured to - receive first signals from the one or more air flow sensors, the first signals being indicative of the respective magnitudes and/or directions of air flow at the respective first one or more positions in the greenhouse, and - receive second signals from the one or more environmental sensors, the second signals being indicative of the respective values of the environmental parameter at the respective second one or more positions in the greenhouse, characterised in that the data processing means is further configured to - determine, based on the first signals and based on the second signals, values of the environmental parameter at third one or more positions in the greenhouse thus determining the distribution in the greenhouse of values of the environmental parameter, wherein the third one or more positions are different from the second one or more positions. one or more air flow sensors for measuring a magnitude and/or direction of air flow at first one or more positions in the greenhouse, and one or more environmental sensors for measuring the values of the environmental parameter at second one or more positions in the greenhouse, and a data processing system that is configured to - receive first signals from the one or more air flow sensors, the first signals being indicative of the respective magnitudes and/or directions of air flow at the respective first one or more positions in the greenhouse, and - receive second signals from the one or more environmental sensors, the second signals being indicative of the respective values of the environmental parameter at the respective second one or more positions in the greenhouse, characterised in that the data processing means is further configured to - determine, based on the first signals and based on the second signals, values of the environmental parameter at third one or more positions in the greenhouse thus determining the distribution in the greenhouse of values of the environmental parameter, wherein the third one or more positions are different from the second one or more positions. - receive first signals from the one or more air flow sensors, the first signals being indicative of the respective magnitudes and/or directions of air flow at the respective first one or more positions in the greenhouse, and - receive second signals from the one or more environmental sensors, the second signals being indicative of the respective values of the environmental parameter at the respective second one or more positions in the greenhouse, characterised in that the data processing means is further configured to - determine, based on the first signals and based on the second signals, values of the environmental parameter at third one or more positions in the greenhouse thus determining the distribution in the greenhouse of values of the environmental parameter, wherein the third one or more positions are different from the second one or more positions.