I was on a multi-day hike (Tasmania, Australia) some years ago, where we would need to know if snow was falling further ahead, as the pass would be difficult in snow, so we would need to turn back in that case; it would be easier to turn back well before reaching the pass. I packed an AM radio to listen to the weather forecast in the morning; before sunrise, the ionosphere reflects AM waves, so the distance of the signal is greatly enhanced (the hike was in a mountainous area and had no straight-line to any radio towers). In fact, I couldn't get the local radio station's reception, but did get reception for heaps of other stations, one of them over 2000km away; I almost wonder if the local station was being drowned out by distant ones (or more likely the ionosphere reflection is better a shallow angles)
While OP is (was) in Australia, for those reading in the US that are interested in something similar, you're better off bringing an FM radio with you that can receive to the NOAA weather radio frequencies, and simply tune to the frequency / channel for your region.
How does this handle situations where you haven't got 'line of sight' (or rather, an unobstructed path) to the transmitter (e.g. when you're nestled in between some mountains)?
VHF (FM radio in the US is in the VHF band) propagation can definitely change at different times of day.
One of my favorite activities in the summer is to go get lost in the Cascades, and when the sun goes down, settle in to a hammock with a little multi-band radio to see what I can pick up. As the evening wears on, I can typically start to receive FM radio stations in Canada several hundred kilometers away. Once the sun has risen again, I can no longer tune those stations no matter how much I fiddle with antenna orientation. NOAA weather bands also become easier to tune clearly at night.
As to why VHF frequencies seem to propagate better at night, I could only speculate, but they do seem to—at least on occasion.
From https://en.wikipedia.org/wiki/Skywave :
> Because the lower-altitude layers (the E-layer in particular) of the ionosphere largely disappear at night, the refractive layer of the ionosphere is much higher above the surface of the Earth at night. This leads to an increase in the "skip" or "hop" distance of the skywave at night.
