SMA PLT INADVERTENTLY FLIES INTO IMC ON A NIGHT VFR FLT.

Narrative

COMING IN FOR A FULL STOP LNDG AT BMG; ASOS RPTED 4000 FT CEILING; 5 SM IN MIST. WHILE APCHING DOWNWIND FOR RWY 24; I FLEW INTO CLOUDS AT 1500 FT MSL. I WAS ATTEMPTING TO AVOID THEM; BUT THEY WERE UNEXPECTED; GIVEN THE ASOS RPT. LAYER SEEMED TO BE A PATCH OF BROKEN. I FLEW THROUGH THEM TO FIND I WAS OVERFLYING THE ARPT RATHER THAN FLYING IN THE PATTERN. I ADVISED TWR; INTERCEPTED DOWNWIND LEG; CONTINUED THE PATTERN; AND LANDED SUCCESSFULLY. I DID ENCOUNTER SMALL CLOUDS IN THE PATTERN; BUT NOT ENOUGH TO OBSCURE SIGHT OF THE RWY. TWR MADE NO MENTION OF THE FACT THAT I FLEW THROUGH ANY CLOUDS. I BELIEVE HE WAS UNAWARE OF THEIR PRESENCE. FLT BRIEFING BEFORE DEP FROM PIA INDICATED VFR ALL THE WAY TO BMG. FURTHER INFO FROM TERRE HAUTE FSS CONFIRMED VFR CONDITIONS WHILE OVERFLYING HUF ALL THE WAY TO BMG. I HAD AN ABORTED TKOF FROM PIA DUE TO WIND GUSTS THAT SCARED ME; AND I WASN'T WATCHING MY ALT CLOSELY ENOUGH AS I WAS APCHING BMG. OTHERWISE; THE FLT WAS ROUTINE. I WAS LIKELY INFLUENCED BY THE FACT THAT I WAS SO CLOSE TO MY DEST THAT I CHOSE TO FLY THROUGH THE CLOUDS RATHER THAN TURN AROUND. NIGHT CONDITIONS ALSO CONTRIBUTED TO THE LATE RECOGNITION OF THE CLOUDS. I DON'T SEE HOW THIS COULD HAVE BEEN AVOIDED OTHER THAN INCREASED VIGILANCE ON MY PART.