Mercury and Venus will be in a close conjunction this evening. While the pair has been drawing closer for the last week, tonight will see them at their closest, about 38′ separation.
Look for the bright planet Venus low in the sunset. Mercury will slightly down and to the north of Venus. A separation of 38′ is just a bit more that the width of the full Moon. Both objects are fairly bright, with Venus shining at -3.9 magnitude and Mercury at -0.7. Bright enough to be quite obvious, the pair will be 17° above the horizon at sunset.
Over the coming week the pair will slightly separate. Mercury will be at maximum elongation on January 14th, after which it will begin its slide back into the sunset.