Question

It is rainy heavy, the strip light had gone off and was retering.....

Answer 1

Before I say anything, let me point out the fact that I only have one season's worth of experience on a British Columbia Unit crew (Canadian hotshots), which still makes me a newbie. Although I now have more knowledge than the average person on forest fires, there are professionals such as fire behaviour specialists, veteran firefighters and meteorologists specializing in wildfire who know infinitely more than I do on this subject.
What I know is from other firefighter's stories, and my limited experience in the field.

How rain can help:

Although it is very unlikely that anything less than a flood will put out a forest fire, rain dramatically brings up the relative humidity slows down the advance of a fire. 
For the same reason that aerial firefighting generally can't stop forest fires alone, rain can't extinguish all the roots and trees that are burning from the inside, but by wetting down the fuels, it can halt a fire very effectively and give us the time we need to contain it and possibly mop it up before the next dry spell.

Now on to how rain may hurt our efforts:

Detecting wildfires early is not easy, many of them are not even started by human activity, but by lighting. Lighting sensors can pinpoint lightning strikes, and provide initial attack crews with accurate locations, however, there are way too many strikes to check them all, and not every strike results in a fire. Furthermore, lightning is often followed by rain, which delays the fire until it dries out enough for adjacent fuels to catch. It's basically a time bomb, lightning hits, the rain keeps it from burning right away, and a week or two later, after the fuel indices have gone down enough, a fire appears seemingly out of thin air in the same spot. 
But this time, unless someone is watching out for smoke, we won't be able to respond as fast.

As for snow, it can have some odd unintended effects on fires. Obviously, the colder temperatures and precipitation do a lot to put out fires. But once again, because it doesn't penetrate very much, there have been cases where a fire just reappeared in the same spot the year after, after we thought the snow put it out.

That's why we'll keep mopping up even when it's raining or snowing, way after a fire has stopped smoking. The lack of smoke doesn't necessarily mean the fire is out, just that it's dormant again.

Some definitions:

Mop up: after a fire has stopped advancing or and has calmed down a lot, firefighters go in the black (charred areas) to manually put out every single ember and dig up and investigate every suspiciously warm dirt. If the fire is small, 100% mop up might be possible, if it's too large, we will do that only to a certain depth from the perimeter. The bigger the fire, the less thorough we can afford to be in order to do the entire perimeter in time.

Fuel indices: Fire centers track various fuel indices such as fine fuel moisture codes (FFMC) Duff moisture code (DMC) and drought code (DC) to help them evaluate risks of fire starts, the depth to which they're likely to burn, the potential rate of spread and what type of fire is likely to result from a start (ground, crown, etc...)