For a process in a small chemical system observed for short periods of time, the probability that it proceeds in the opposite direction to that found in the thermodynamic limit can be significant. We demonstrate this using simulations of a hydrogenbonded network of water molecules whose temperature is changed from 300 K to 310 K. It is shown that for this system, and finite periods (up to tenths of picoseconds), the change during an individual observation period might be in either direction which satisfies the transient fluctuation theorem for a temperature change