Speculative purchases by traders have driven wheat prices up by 2.7-3.8% on US exchanges due to concerns over potential crop damage from anticipated frost and lack of snow cover in the US and Ukraine. The US is expected to experience extreme cold temperatures next week, while Ukraine faces concerns of reduced soil moisture reserves and crop condition worsening. However, favorable European weather conditions have limited the price increase in the Euronext exchange in Paris. The market's speculative pressure is expected to lessen over the weekend with the assessment of potential crop damage, as temperatures in the US and Ukraine rise above 0°C and there is minor precipitation.