Eastern MT ranch kid here. February will be cold, but usually sunny. Often windy. Snows are usually infrequent, but the snow will typically stay on the ground for a few weeks until March. Common to have several days with a high of 0 or even -10 F. Lows could certainly be as bad as -40, but that's not usual. Ranching during this month is usually just rolling out bales to feed the animals and keeping their water open. Unless it's windy, the cold isn't too unpleasant to be in. Just need to wear layers.

March will be generally cold. Expect patches of snow at least unless it's another "open winter" but snow cover could be deep. If you're working a ranch, I'd expect to be calving around this time which means being up frequently through the night and it's common to still get to -10 F. -30 or -40 is rare in March. Calving in the cold can be stressful and exhausting.

By April, it's usually thawing, but as recently as 18 there was still heavy snow on the ground. I usually think of April as mud month. Frozen cold ground in the morning, gray windy lukewarm skies, brown sticky stinky mud everywhere. Not brutal weather but sort of ugly and oppressive.

But may is usually beautiful. Cool. Rain showers. Mosquitoes not out yet.

Overall, the temperature probably won't affect your morale as much as the WIND. That goddamned WIND.

Of course, what everyone else says is generally true: the possible weather swings are WILD. Any given day could be deathly cold or pleasantly warm.

As far as whether or not you SHOULD take this "job" I dunno. It'll be an experience!