Discount hotel promotions can arise any day, any hour. But hotel specials particularly pop up during the midweek malaise. Then, before you know it, the discounts disappear again. Here's how to make sure you won't miss out.

Every Tuesday, Hotels.com hosts a 24-hour sale with rates that can be up to 40 percent lower than normal at properties all over the world, including New York City and Orlando. You don't have to actually stay over in the hotel on a Tuesday; it's just the only day you can book and get the hefty discount.

Tuesday is also the big discount day for last-minute bookings with All Seasons Hotels, a solid brand affiliated with hotel giant Accor. When you book on a Tuesday with All Seasons, you can get two nights for the price of one for the upcoming weekend. A hotel in Orleans, France, for example, that was normally $85 per night is suddenly yours for Friday and Saturday night at that rate. FYI, All Seasons has more than 30 hotels—most in Europe, with a particularly big presence in France.

Hump Day, meanwhile, is when Sol Melia Hotels announces Wednesday Web Weekend specials—deals for the upcoming weekend. A recent example: the four-star Tryp Diana hotel, at the airport in Madrid, Spain, was under $80 a night.

Unfamiliar with these brands? Check out these and others in our story on 39 affordable hotel chains only locals know about.

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