To travel 100 miles it takes the same amount of time both in summer and in winter.
The only difference is that in winter you will make double the number of fatigue tests and you will get double the number of fatigue points if failed.
Is this correct?

That's right by the rules.

Of course the LM might fiddle with TNs and will probably come up with seasonal hazards.

Agreed that there doesn't seem to be anything changing speed of travel for season. Implicitly more frequent checks may mean wanting more lay-overs and thus taking longer, but this doesn't actually reflect "slower going slogging through snow".

A GM could, however, easily use the Terrain Difficulty table on page 32 of Loremaster's book and bump up to the next difficulty for poor weather conditions that affect speed of travel, and snow on the ground is an actual "terrain" not just a weather (I would make a respectable snowfall at least Moderate Terrain for example).

Of course, heroes should all be tucked away in havens singing songs and otherwise enjoying a good Fellowship phase if they're smart - not slogging through snowstorms.

Rob

Many Hazards also delay the PCs and make the journey longer, which would be more likely in Winter than in Summer.

Forgive me for asking, but are there any mechanics that make hazards more likely (or more difficult, or with a harsher baseline, etc) if they take place in the winter instead of the summer?

You make double the number of fatigue tests in winter so it's more likely you'll get a hazard.

Describing the hazard is up to the GM and adding travel time is a common consequence.