It was the first time since April 10 that the bank did not let the pound weaken at a dollar auction. Sisi, who toppled Egypt's first freely elected leader last July following mass protests, took more than 90 percent of the vote and joins a long line of leaders drawn from the military.
The central bank kept its overnight deposit rate and the overnight lending rate at 8.25 percent and 9.25 percent, respectively, it said on Thursday.
Egypt wants to boost its economy damaged by three years of social and political upheaval that has unnerved foreign investors and tourists and led to dollar shortages and fuelled a thriving black market.
The central bank said it sold $37.6 million at a cut-off price of 7.1404 pounds, unchanged from its last sale on Thursday.
It had offered $40 million.
Forex traders and economists have described the central bank's decision to allow the pound to gradually weaken in recent weeks as a managed depreciation. The central bank has not said why it has let the currency weaken.
The rates at which banks are allowed to trade dollars are determined by the results of the central bank sales, giving the bank effective control over official exchange rates.
One black market trader put Monday's rate at 7.45/47 pounds to the dollar, in line with Sunday's prices. On Thursday the pound traded at 7.50/53 pounds to the dollar.
A weaker currency could help the country's economy, currently growing around 2 percent, by making Egyptian exports more competitive, economists have said.