In our crew I'm the only one with any real boating/yachting experience (though none of it recent!), so I'm on solid footing with that sort of thing as DM and often have to chime in as a player when such things come up. I'm also well-versed in weather - I was a weather geek long before I became a D&D geek - and describing realistic weather can really help set the tone and make the world believable.
I love weather, too. Love reading forecasts. In '93 or so I went to my college library and got microfiche of the newspaper for every day of the year (Billings Gazette while at Montana State University) to see just how accurate forecasts were.
Oh, to have had a proper spreadsheet program instead of doing it by hand. Montana weather is quite variable so accurate forecasts can be difficult when trying to time when fronts roll through. Being off by a little bit in timing can mean a lot of degrees.
In any event, I found two results. One: forecasts (and five-day was the longest at the time) were more accurate the shorter the time frame. That is, a forecast one day out was more accurate than one five days out. This isn't surprising and what we would hope to be the case. Result two: forecasts were consistently too conservative. That is, if the forecast was for the temperature to be above average it was warmer than predicted. If the forecast was for the temperature to be below average it was colder than predicted. This was consistent day after day, month after month.
But back to D&D! Because of the internet we can go to wunderground.com and get historical hourly weather for hundreds of locations in the United States. Pick a location with weather you believe mimics your fantasy location. Pick a year. Instant perfectly believable weather!
My current campaign is set in Mystara. The first Gazetteer was published in 1987, so I picked 1987 for the year. I picked Roanoke, VA to mimic the town from the setting, Threshold. The Mystara map is earth from 150 million years ago, so Threshold is basically in the foothills of the Appalachians and that's exactly where Roanoke is. Turns out 1987 was a nasty Winter with lots of wet snow. It really affected the game! The PCs decided not to take the hook and do
Keep on the Borderlands But the snow in the mountains was so bad it drove the humanoids out of the caves and they overran the undermanned keep.
Massive record breaking rains slowed the PCs on their way to get one of them cured of lycanthropy before it killed her (as it does to demihumans in BECMI D&D). It certainly added tension and the PCs outright skipped some things just to get where they were going. Plus, the PCs don't think I'm out to get them or, conversely, making it easier on them when the temperatures hit the '80s in May and travel was easy. Many picnics were had after that awful Winter!
Sure, it takes lots of prep but I enjoy it. It's also the type of DMing I like. Once the game starts I try to be as neutral as I can be.