Bacteria is why we refrigerate meat. Salmonella and E. coli in your roast will ruin its even cooking.
These bacteria flourish at certain temperatures.
The USDA labels it the "danger zone," 40–140 degrees Fahrenheit.
Therefore, steak should be cooked to 145 degrees Fahrenheit and refrigerators maintained below 40 degrees.
Your roast should not be left at room temperature for more than two hours to keep safe to eat.
In hot climates, this window is significantly shorter. If the air is 90 degrees or higher, meat cannot be left out for more than an hour.
However, if you stick to the prescribed time range, you should have the perfect roast.