I'm not entirely sure what any of this means, or why, but these errors are consistently generated during the rain, and the game slows down to such a degree that I have to close and re-open it if I want to play. It's crippling enough that I have wanted to restart saves just because I don't think I will reasonably get past the turns that the rain lasts (or else, suffer the rain yet again). It seems to get worse the more times it happens in a certain save, but I'm not entirely certain on that.
It happens consistently during rain, and ceases when the rain ends. Error logs below (some of them likely not actually related to the rain, but all included and unchanged in case it helps).
EDIT: Actually, this time it has completely bricked the save. I'm keeping it around in case it needs looking at, but it's completely unplayable.
[10:25:32] [warning] Map data/mods/core/maps\map_30_0_0.smap skipped because no name has been assigned.
[10:25:32] [warning] Map data/mods/core/maps\map_30_2_0.smap skipped because no name has been assigned.
[10:25:32] [warning] Map data/mods/core/maps\map_30_3_0.smap skipped because no name has been assigned.
[10:25:32] [warning] Map data/mods/core/maps\map_31_0_0.smap skipped because no name has been assigned.
[10:25:33] [warning] Map data/mods/core/maps\map_31_2_0.smap skipped because no name has been assigned.
[10:25:33] [warning] Map data/mods/core/maps\map_31_3_0.smap skipped because no name has been assigned.
[10:25:34] [warning] Map data/mods/core/maps\map_3_28_0.smap skipped because no name has been assigned.
[10:25:34] [warning] Map data/mods/core/maps\map_3_30_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_30_0_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_30_2_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_30_3_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_31_0_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_31_2_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_31_3_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_3_28_0.smap skipped because no name has been assigned.
[10:25:42] [warning] Map data/mods/core/maps\map_3_30_0.smap skipped because no name has been assigned.
[10:26:05] [critical] Unable to save '1480616' on map 29,29,0, current position 30,28,0, entity doesn't exist.
[10:26:06] [warning] AIMovement: Entity 1480884 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:07] [error] Producing: Distance to target 1476122 is 8, too far - clearing action.
[10:26:17] [critical] Unable to save '1480621' on map 29,29,0, current position 29,29,0, entity doesn't exist.
[10:26:17] [warning] AIMovement: Entity 1490184 path to the tile 1839,1834 could not be found! Clearing actions.
[10:26:17] [warning] AIMovement: Entity 1490184 path to the tile 1839,1834 could not be found! Clearing actions.
[10:26:18] [critical] Unable to save '1478305' on map 29,29,0, current position 29,29,0, entity doesn't exist.
[10:26:18] [warning] AIMovement: Entity 1490119 path to the tile 1829,1828,0 could not be found! Popping move action.
[10:26:18] [warning] AIMovement: Entity 1490119 path to the tile 1829,1828 could not be found! Clearing actions.
[10:26:23] [warning] AIMovement: Entity 1490104 path to the tile 1829,1828,0 could not be found! Popping move action.
[10:26:23] [warning] AIMovement: Entity 1490104 path to the tile 1829,1828 could not be found! Clearing actions.
[10:26:24] [warning] AIMovement: Entity 1490059 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:31] [warning] AIMovement: Entity 1480840 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:33] [warning] AIMovement: Entity 1480851 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:33] [warning] AIMovement: Entity 1480840 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:34] [warning] AIMovement: Entity 1478043 path to the tile 1961,1941 could not be found! Clearing actions.
[10:26:34] [warning] AIMovement: Entity 1490104 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:38] [warning] AIMovement: Entity 1490165 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:39] [warning] AIMovement: Entity 1480851 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.
[10:26:41] [critical] Unable to save '1480572' on map 29,30,0, current position 29,29,0, entity doesn't exist.
[10:26:42] [warning] AIMovement: Entity 1480840 path to the tile -10000000,-10000000,-10000000 could not be found! Popping move action.