Many pilots will have more authoritative remarks about IFR flight than I. It has been 25 years since I did any amount of IFR flying. I will acceed to the wisdom of those pilots.
That said, I have just never felt that a systems and performance limited aircraft like a 150 has much role in IFR flight, other than perhaps awareness training. If you're thinking of all weather flying, I suggest you need more aircraft than a 150, regardless of the temperature.
My limited experience with "warm weather" IFR flight has taught me to be aware of thunderstorms, and fog. Both of these forms of adverse weather are every bit as challenging to safety, as the challenges of cold weather IFR flight.
But, the thread drifts a little... To get the best opinionon IFR flight, from those who really know, may I suggest starting a thread "Does a C 150 belong in IFR flight conditions?"
In the mean time, 150's, and many similar aircraft, are marvelous, and economical means to get safety airborne. Plan to use them the way they were intended. In appropriate weather, I have flown my 150 west as far as Kansas City, east as far as Cape Breton, North to mid Ontario and Manitoba, and south to Key West, and the Bahamas (with my wife, and two folding bikes) 150's are remarkably versitile.