1. Market sentiment: The decline in crude oil futures prices may reflect the market's concerns about crude oil demand and supply. This may be due to factors such as slowing global economic growth and increasing geopolitical risks.

2. Supply and demand: the change of crude oil price depends largely on the supply and demand. If the supply is sufficient and the demand decreases, the price may fall. In addition, the inventory level and production data will also affect the oil price trend.

3. Investor expectation: The fluctuation of crude oil futures price is greatly influenced by investor expectation. If the market expects an increase in crude oil supply or a decrease in demand in the future, the price may fall.

4. Exchange rate fluctuations: crude oil prices are usually negatively correlated with the exchange rate of the US dollar. When the dollar strengthens, the price of crude oil tends to fall; On the contrary, when the dollar is weak, the price of crude oil rises. Therefore, exchange rate fluctuations may also be one of the reasons for the decline in crude oil futures prices.

5. Technical analysis: From the perspective of technical analysis, the decline of crude oil futures price may be due to the technical adjustment of the market in the short term. In technical analysis, there are many indicators that can be used to judge the price trend, such as moving average, bollinger band, MACD and so on. These indicators may indicate that the market is overbought or oversold, leading to a price correction.

In short, the 2.46% decline of crude oil futures at night may be the result of a combination of many factors. To accurately judge the reasons behind this phenomenon, it is necessary to comprehensively analyze various market information and data.