Swenstown, like most of Eastern Sartar, is in the rain shadow of the Quivin and Storm Mountains (and of course the Rockwoods as well). No gentle summer rains there – on average Swenstown receives no rain at all in Fire Season, and only 8 cm through the middle of Dark Season. By middle Dark Season, it is dry indeed. Instead, Swenstown receives over 80% of its precipitation from Storm through Sea Season.
You can see this dry period throughout the Guardian Hills. The Quivin River is normally nothing more than a trickle in Toena in late Earth Season/early Dark Season. This is enough for the grasslands around Swenstown to look fantastically rich to the Praxians, but it is semi-arid country.
Remember, Swenstown is on the edge of Prax. Pimper’s Block is only about 20 km away, Moonbroth 48 km, and the Dead Place a little over 50 km away. We usually say Pimper’s Block is in Prax (even if it is politically part of Sartar), but the Nomad Gods map ends one hex before Swenstown.
The western side of Sartar gets much more rainfall – some places (like Clearwine) get twice as much precipitation as the Guardian Hills. So even though Clearwine and Swenstown are only about 75 km away (as the dragon flies), they are in very different biomes.
Swenstown is closer to the Dead Place than it is to Clearwine.
Remember, many of the rivers in eastern Sartar are seasonal. The Jorazi (which drains the Dundealos Valley) dries up every fall, and the Quivin past Toena Fort becomes a trickle in Autumn. The Dozalin dries up every fall. And even the Lorthing River becomes a trickle in Fox Hollow.
But in Sea Season and early Fire Season, the Quivin River runs all the way to the Dead Place! All that rain and snowmelt comes down and makes it all the way to the salt flats.
Past Swenstown is the Pol Joni March, good rangeland for cattle and horses. Think of it as a belt of open range, about 100 km long and maybe 10-15 km wide. Traditionally, that’s been the home of the Pol Joni, although post 1608 they’ve had to contend with Sable dominance in the Good Place and Better Place, and many Pol-Joni had to take to the rangelands around Barbarian Town.