My 2 battery’s are brand new and I only get 21 minutes till 10% for each of them, is this Normal? (Flying in 25F weather)

Sounds normal to me? Here are the specs:
Max Flight Time        27 minutes (no wind at a consistent 15.5 mph (25 kph))
Max Hovering Time        24 minutes (no wind)
Overall Flight Time        21 minutes ( In normal flight, 15% remaining battery level )

Yeah this sounds normal. I get around 20 to 24 mins of flight time usually.

It doesn't seem abnormal, refer to the specs below, and the flight time might vary from the practical flight, environment, takeoff altitude etc., some of the controls might speed up the consumption of the power.

Note that wind speed, air temperature, air pressure in line with elevation to sea level and how you fly the drone will all impact on the battery performance. Sport mode, 100% pitch/throttle for prolonged periods on distance flying, hovering for long periods etc will all add to a quicker flight time. You’ll tend to get longer flights on the second battery as the drone would have warmed through from the first flight. If you use the new 8331 props you can add a minute to those times noted above and three added minutes with the Mavic Platinum - my longest flight time on my MPP is 27:53 and that was in -1c temps and using Sport mode for bit! I average around 25 minutes per flight from 100% down to 15% upon turning off the battery.