Yes, the IRS states that they issue most refunds within 21 days, so that does include the weekends. If the IRS needs more information from you to process your return, then they will contact you by mail.
See: What Days of the Week Does the IRS Deposit Tax Refunds? https://turbotax.intuit.com/tax-tools/tax-tips/General-Tax-Tips/Video--What-Days-of-the-Week-Does-th... The IRS only updates your refund status information once per week on Wednesdays.
