The folks at RealtyTrac set out to answer an eternal question: When is the best time of the year to buy a home? Everyone’s had a real estate agent tell them to buy during the fall and winter months, but is this true?

Using big data—comparing average sale prices to average estimated market value at time of sale for 32 million single-family home and condo sales over the past 15 years—RealtyTrac determined when buyers paid a premium or bought at a discount. Then, based on the sale’s closing date, RealtyTrac identified the month, day and weekday with the biggest discounts.

Based on the above chart, it seems that October is the best month to close a purchase on a home, with an average discount of 2.6% below full estimated market value of time of sale, followed by February, July, December and January. April is the worst, with a dismal average premium 1.2% above estimated market value.

In fact, RealtyTrac was even able to pinpoint Oct. 8 as the best day to buy a home, with a startling 10.8% below estimated market value. Nov. 26 (10.1%), Dec. 31 (9.7%), Oct. 22 (9.6%) and Oct. 15 (9.1%) also have huge discounts, while Jan. 19 (9.6%), Feb. 16 (9.5%), April 20 (9.5%), April 6 (8.4%) and April 27 (8.2%) are the days with the largest premiums.

As for weekday, you should be looking to close a purchase on a Monday or Friday, as you can get a 2.3% or 2% discount, respectively. But stay away on Thursdays (1% discount), Wednesdays (1.4% discount) and Tuesdays (1.9% discount).

RealtyTrac has even provided an interactive visual of the data for major markets, which you can see here.