In a METAR or TAF report, BECMG means “becoming.”

Here’s an example from one of our practice questions:

(Refer to Figure 15) In the TAF from KOKC, the clear sky becomes
A) overcast at 2,000 feet during the forecast period between 2200Z and 2400Z.
B) overcast at 200 feet with a 40% probability of becoming overcast at 600 feet during the forecast period between 2200Z and 2400Z.
C) overcast at 200 feet with a probability of becoming overcast at 400 feet during the forecast period between 2200Z and 2400Z.

We can see in each of the answer choices that we’re being asked to look at the forecast period between 2200Z and 2400Z. So let’s isolate that part of the TAF report, which says:

SKC BECMG 0522/0524 20013G20KT 4SM SHRA OVC020

This translates to — clear skies becoming from 2200Z to 2400Z on the 5th, winds from 200° at 13 knots gusting up to 20 knots, visibility 4 statute miles, rain showers, clouds overcast at 2,000 ft.