It has been asserted that: ‘It is difficult to conceive just how any force could have benefited more from the weakness and mistakes of its enemy than the German Army did from those of the Poles in 1939.’ The German army had been prepared for war with Poland both in strategic terms as well as political. The signing of the agreement with the Soviet Union removed the last possible unknown element in the army's calculations and thus few, if any, preparations were made for intervention from either the west or the east in the event of a German attack on Poland.

The conclusion of the Anglo–Polish pact on 25 August briefly caused Hitler to postpone the attack. The element of surprise was lost, but what was gained was full state of mobilisation. On 30 August the final order was given by Hitler to attack Poland on 1 September at 04.30 hours and ‘at the same time he strictly forbade any offensive action, or indeed anything that might be taken as a provocation, on the western frontiers with France or with the neutral states’. The attack could not be postponed further as it was feared that the autumn rains would start. This was a point of which the Poles were aware and one which they considered to be a strength in their defensive plans, as they knew the roads to be impassable once autumn started.