diff --git a/src/config/generation.ts b/src/config/generation.ts
index 95ee79f2..ff17126d 100644
--- a/src/config/generation.ts
+++ b/src/config/generation.ts
@@ -5,5 +5,6 @@ export const MAX_HEIGHT = 100;
 export enum DISTANCE_FIELD {
   LAND_COAST = 1,
   UNMARKED = 0,
-  WATER_COAST = -1
+  WATER_COAST = -1,
+  DEEPER_WATER = -2
 }
diff --git a/src/dialogs/dialogs/heightmap-editor.js b/src/dialogs/dialogs/heightmap-editor.js
index 0ecfdd2e..097a0a74 100644
--- a/src/dialogs/dialogs/heightmap-editor.js
+++ b/src/dialogs/dialogs/heightmap-editor.js
@@ -221,9 +221,9 @@ export function open(options) {
       Lakes.openNearSeaLakes(grid);
     }
     OceanLayers(grid);
-    calculateTemperatures();
-    generatePrecipitation();
-    reGraph();
+    calculateTemperatures(grid);
+    generatePrecipitation(grid);
+    reGraph(grid);
     drawCoastline();
 
     Rivers.generate(erosionAllowed);
@@ -340,9 +340,9 @@ export function open(options) {
 
     if (erosionAllowed) addLakesInDeepDepressions();
     OceanLayers(grid);
-    calculateTemperatures();
-    generatePrecipitation();
-    reGraph();
+    calculateTemperatures(grid);
+    generatePrecipitation(grid);
+    reGraph(grid);
     drawCoastline();
 
     if (erosionAllowed) Rivers.generate(true);
diff --git a/src/dialogs/dialogs/units-editor.js b/src/dialogs/dialogs/units-editor.js
index 2dcea13c..43b6eb48 100644
--- a/src/dialogs/dialogs/units-editor.js
+++ b/src/dialogs/dialogs/units-editor.js
@@ -83,7 +83,7 @@ export function open() {
   }
 
   function changeHeightExponent() {
-    calculateTemperatures();
+    calculateTemperatures(grid);
     if (layerIsOn("toggleTemp")) drawTemp();
   }
 
@@ -134,7 +134,7 @@ export function open() {
     // height exponent
     heightExponentInput.value = heightExponentOutput.value = 1.8;
     localStorage.removeItem("heightExponent");
-    calculateTemperatures();
+    calculateTemperatures(grid);
 
     // scale bar
     barSizeOutput.value = barSizeInput.value = 2;
diff --git a/src/modules/io/load.js b/src/modules/io/load.js
index 98c12374..d63414bc 100644
--- a/src/modules/io/load.js
+++ b/src/modules/io/load.js
@@ -399,7 +399,7 @@ async function parseLoadedData(data) {
     })();
 
     void (function parsePackData() {
-      reGraph();
+      reGraph(grid);
       reMarkFeatures();
       pack.features = JSON.parse(data[12]);
       pack.cultures = JSON.parse(data[13]);
diff --git a/src/modules/markup.ts b/src/modules/markup.ts
index 57af2bcd..b3b9054d 100644
--- a/src/modules/markup.ts
+++ b/src/modules/markup.ts
@@ -7,7 +7,7 @@ import {aleaPRNG} from "scripts/aleaPRNG";
 const {UNMARKED, LAND_COAST, WATER_COAST} = DISTANCE_FIELD;
 
 // define features (grid.features: ocean, lakes, islands) and calculate distance field (cells.t)
-export function markupGridFeatures(grid: IGraph & {cells: {h: UintArray}}) {
+export function markupGridFeatures(grid: IGridWithHeights) {
   TIME && console.time("markupGridFeatures");
   Math.random = aleaPRNG(seed); // get the same result on heightmap edit in Erase mode
 
@@ -173,8 +173,10 @@ export function reMarkFeatures() {
     return "gulf";
   }
 
-  function defineIslandGroup(cell, number) {
-    if (cell && features[cells.f[cell - 1]].type === "lake") return "lake_island";
+  function defineIslandGroup(cellId: number, number: number) {
+    const prevCellFeature = features[cells.f[cellId - 1]];
+
+    if (cellId && prevCellFeature && prevCellFeature.type === "lake") return "lake_island";
     if (number > grid.cells.i.length / 10) return "continent";
     if (number > grid.cells.i.length / 1000) return "island";
     return "isle";
diff --git a/src/modules/precipitation.js b/src/modules/precipitation.js
index e77c8053..aea8c8fe 100644
--- a/src/modules/precipitation.js
+++ b/src/modules/precipitation.js
@@ -5,11 +5,12 @@ import {minmax} from "utils/numberUtils";
 import {rand} from "utils/probabilityUtils";
 
 // simplest precipitation model
-export function generatePrecipitation() {
+export function generatePrecipitation(grid) {
   TIME && console.time("generatePrecipitation");
   prec.selectAll("*").remove();
+
   const {cells, cellsX, cellsY} = grid;
-  cells.prec = new Uint8Array(cells.i.length); // precipitation array
+  const precipitation = new Uint8Array(cells.i.length); // precipitation array
 
   const cellsNumberModifier = (pointsInput.dataset.cells / 10000) ** 0.25;
   const precInputModifier = precInput.value / 100;
@@ -94,20 +95,20 @@ export function generatePrecipitation() {
         if (cells.h[current] < 20) {
           // water cell
           if (cells.h[current + next] >= 20) {
-            cells.prec[current + next] += Math.max(humidity / rand(10, 20), 1); // coastal precipitation
+            precipitation[current + next] += Math.max(humidity / rand(10, 20), 1); // coastal precipitation
           } else {
             humidity = Math.min(humidity + 5 * modifier, maxPrec); // wind gets more humidity passing water cell
-            cells.prec[current] += 5 * modifier; // water cells precipitation (need to correctly pour water through lakes)
+            precipitation[current] += 5 * modifier; // water cells precipitation (need to correctly pour water through lakes)
           }
           continue;
         }
 
         // land cell
         const isPassable = cells.h[current + next] <= MAX_PASSABLE_ELEVATION;
-        const precipitation = isPassable ? getPrecipitation(humidity, current, next) : humidity;
-        cells.prec[current] += precipitation;
-        const evaporation = precipitation > 1.5 ? 1 : 0; // some humidity evaporates back to the atmosphere
-        humidity = isPassable ? minmax(humidity - precipitation + evaporation, 0, maxPrec) : 0;
+        const cellPrec = isPassable ? getPrecipitation(humidity, current, next) : humidity;
+        precipitation[current] += cellPrec;
+        const evaporation = cellPrec > 1.5 ? 1 : 0; // some humidity evaporates back to the atmosphere
+        humidity = isPassable ? minmax(humidity - cellPrec + evaporation, 0, maxPrec) : 0;
       }
     }
   }
@@ -162,4 +163,5 @@ export function generatePrecipitation() {
   })();
 
   TIME && console.timeEnd("generatePrecipitation");
+  return precipitation;
 }
diff --git a/src/modules/submap.js b/src/modules/submap.js
index b67bb90e..e7ff76f9 100644
--- a/src/modules/submap.js
+++ b/src/modules/submap.js
@@ -125,10 +125,8 @@ window.Submap = (function () {
     OceanLayers(grid);
 
     calculateMapCoordinates();
-    // calculateTemperatures();
-    // generatePrecipitation();
     stage("Cell cleanup.");
-    reGraph();
+    reGraph(grid);
 
     // remove misclassified cells
     stage("Define coastline.");
diff --git a/src/modules/temperature.js b/src/modules/temperature.js
deleted file mode 100644
index c1a3c3b2..00000000
--- a/src/modules/temperature.js
+++ /dev/null
@@ -1,35 +0,0 @@
-import * as d3 from "d3";
-
-import {TIME} from "config/logging";
-import {minmax, rn} from "utils/numberUtils";
-
-// temperature model
-export function calculateTemperatures() {
-  TIME && console.time("calculateTemperatures");
-  const cells = grid.cells;
-  cells.temp = new Int8Array(cells.i.length); // temperature array
-
-  const tEq = +temperatureEquatorInput.value;
-  const tPole = +temperaturePoleInput.value;
-  const tDelta = tEq - tPole;
-  const int = d3.easePolyInOut.exponent(0.5); // interpolation function
-
-  d3.range(0, cells.i.length, grid.cellsX).forEach(function (r) {
-    const y = grid.points[r][1];
-    const lat = Math.abs(mapCoordinates.latN - (y / graphHeight) * mapCoordinates.latT); // [0; 90]
-    const initTemp = tEq - int(lat / 90) * tDelta;
-    for (let i = r; i < r + grid.cellsX; i++) {
-      cells.temp[i] = minmax(initTemp - convertToFriendly(cells.h[i]), -128, 127);
-    }
-  });
-
-  // temperature decreases by 6.5 degree C per 1km
-  function convertToFriendly(h) {
-    if (h < 20) return 0;
-    const exponent = +heightExponentInput.value;
-    const height = Math.pow(h - 18, exponent);
-    return rn((height / 1000) * 6.5);
-  }
-
-  TIME && console.timeEnd("calculateTemperatures");
-}
diff --git a/src/modules/temperature.ts b/src/modules/temperature.ts
new file mode 100644
index 00000000..5a5d3c41
--- /dev/null
+++ b/src/modules/temperature.ts
@@ -0,0 +1,47 @@
+import * as d3 from "d3";
+
+import {TIME} from "config/logging";
+import {minmax} from "utils/numberUtils";
+import {getInputNumber} from "utils/nodeUtils";
+import {MIN_LAND_HEIGHT} from "config/generation";
+
+const interpolate = d3.easePolyInOut.exponent(0.5); // interpolation function
+
+export function calculateTemperatures(grid: IGridWithHeights) {
+  TIME && console.time("calculateTemperatures");
+
+  const {cells, cellsX, points} = grid;
+  const heights = cells.h;
+
+  const temperatures = new Int8Array(heights.length); // temperature array
+
+  // temperature decreases by 6.5 Celsius per kilometer
+  const heightExponent = getInputNumber("heightExponentInput");
+  function decreaseTempFromElevation(height: number) {
+    if (height < MIN_LAND_HEIGHT) return 0;
+
+    const realHeight = Math.pow(height - 18, heightExponent);
+    return (realHeight / 1000) * 6.5;
+  }
+
+  const tEq = getInputNumber("temperatureEquatorInput");
+  const tPole = getInputNumber("temperaturePoleInput");
+  const tDelta = tEq - tPole;
+
+  const {latN, latT} = window.mapCoordinates;
+
+  d3.range(0, heights.length, cellsX).forEach(rowStart => {
+    const y = points[rowStart][1];
+    const lat = Math.abs(latN - (y / graphHeight) * latT); // [0; 90]
+
+    const initTemp = tEq - interpolate(lat / 90) * tDelta;
+    for (let i = rowStart; i < rowStart + cellsX; i++) {
+      const elevationDecrease = decreaseTempFromElevation(heights[i]);
+      temperatures[i] = minmax(initTemp - elevationDecrease, -128, 127);
+    }
+  });
+
+  TIME && console.timeEnd("calculateTemperatures");
+
+  return temperatures;
+}
diff --git a/src/modules/ui/world-configurator.js b/src/modules/ui/world-configurator.js
index 50146498..ba4d42ac 100644
--- a/src/modules/ui/world-configurator.js
+++ b/src/modules/ui/world-configurator.js
@@ -60,8 +60,8 @@ export function editWorld() {
 
     updateGlobeTemperature();
     updateGlobePosition();
-    calculateTemperatures();
-    generatePrecipitation();
+    calculateTemperatures(grid);
+    generatePrecipitation(grid);
     const heights = new Uint8Array(pack.cells.h);
     Rivers.generate();
     Lakes.defineGroup();
diff --git a/src/scripts/generation.ts b/src/scripts/generation.ts
index 9cd9ab15..c3c26e9c 100644
--- a/src/scripts/generation.ts
+++ b/src/scripts/generation.ts
@@ -3,16 +3,24 @@ import * as d3 from "d3";
 import {ERROR, INFO, WARN} from "config/logging";
 import {closeDialogs} from "dialogs/utils";
 import {initLayers, renderLayer, restoreLayers} from "layers";
+// @ts-expect-error js module
 import {drawCoastline} from "modules/coastline";
 import {calculateMapCoordinates, defineMapSize} from "modules/coordinates";
-import {markupGridFeatures, markupGridOcean} from "modules/markup";
+import {markupGridFeatures} from "modules/markup";
+// @ts-expect-error js module
 import {drawScaleBar, Rulers} from "modules/measurers";
+// @ts-expect-error js module
 import {generatePrecipitation} from "modules/precipitation";
 import {calculateTemperatures} from "modules/temperature";
+// @ts-expect-error js module
 import {unfog} from "modules/ui/editors";
+// @ts-expect-error js module
 import {applyMapSize, randomizeOptions} from "modules/ui/options";
+// @ts-expect-error js module
 import {applyStyleOnLoad} from "modules/ui/stylePresets";
+// @ts-expect-error js module
 import {addZones} from "modules/zones";
+// @ts-expect-error js module
 import {aleaPRNG} from "scripts/aleaPRNG";
 import {hideLoading, showLoading} from "scripts/loading";
 import {clearMainTip, tip} from "scripts/tooltips";
@@ -45,9 +53,9 @@ export async function generate(options?: IGenerationOptions) {
     applyMapSize();
     randomizeOptions();
 
-    const updatedGrid = await updateGrid(precreatedGraph);
+    const updatedGrid = await updateGrid(grid, precreatedGraph);
 
-    reGraph();
+    reGraph(updatedGrid);
     drawCoastline();
 
     Rivers.generate();
@@ -75,6 +83,8 @@ export async function generate(options?: IGenerationOptions) {
     Markers.generate();
     addZones();
 
+    OceanLayers(updatedGrid);
+
     drawScaleBar(scale);
     Names.getMapName();
 
@@ -110,35 +120,33 @@ export async function generate(options?: IGenerationOptions) {
   }
 }
 
-async function updateGrid(precreatedGraph?: IGrid) {
-  const globalGrid = grid;
-
-  const updatedGrid: IGraph & Partial<IGrid> = shouldRegenerateGridPoints(globalGrid)
+async function updateGrid(globalGrid: IGrid, precreatedGraph?: IGrid): Promise<IGrid> {
+  const baseGrid: IGridBase = shouldRegenerateGridPoints(globalGrid)
     ? (precreatedGraph && undressGrid(precreatedGraph)) || generateGrid()
     : undressGrid(globalGrid);
 
-  const heights = await HeightmapGenerator.generate(updatedGrid);
-  updatedGrid.cells.h = heights;
+  const heights: Uint8Array = await HeightmapGenerator.generate(baseGrid);
+  if (!heights) throw new Error("Heightmap generation failed");
+  const heightsGrid = {...baseGrid, cells: {...baseGrid.cells, h: heights}};
 
-  const {featureIds, distanceField, features} = markupGridFeatures(updatedGrid);
-  updatedGrid.cells.f = featureIds;
-  updatedGrid.cells.t = distanceField;
-  updatedGrid.features = features;
+  const {featureIds, distanceField, features} = markupGridFeatures(heightsGrid);
+  const markedGrid = {...heightsGrid, features, cells: {...heightsGrid.cells, f: featureIds, t: distanceField}};
 
   const touchesEdges = features.some(feature => feature && feature.land && feature.border);
   defineMapSize(touchesEdges);
-
-  Lakes.addLakesInDeepDepressions(updatedGrid);
-  Lakes.openNearSeaLakes(updatedGrid);
-
-  OceanLayers(updatedGrid);
-
   window.mapCoordinates = calculateMapCoordinates();
-  calculateTemperatures();
-  generatePrecipitation();
+
+  Lakes.addLakesInDeepDepressions(markedGrid);
+  Lakes.openNearSeaLakes(markedGrid);
+
+  const temperature = calculateTemperatures(markedGrid);
+  const temperatureGrid = {...markedGrid, cells: {...markedGrid.cells, temp: temperature}};
+
+  const prec = generatePrecipitation(temperatureGrid);
+  return {...temperatureGrid, cells: {...temperatureGrid.cells, prec}};
 }
 
-function undressGrid(extendedGrid: IGrid) {
+function undressGrid(extendedGrid: IGrid): IGridBase {
   const {spacing, cellsDesired, boundary, points, cellsX, cellsY, cells, vertices} = extendedGrid;
   const {i, b, c, v} = cells;
   return {spacing, cellsDesired, boundary, points, cellsX, cellsY, cells: {i, b, c, v}, vertices};
@@ -154,12 +162,17 @@ export async function generateMapOnLoad() {
 // clear the map
 export function undraw() {
   viewbox.selectAll("path, circle, polygon, line, text, use, #zones > g, #armies > g, #ruler > g").remove();
+
   byId("deftemp")
-    .querySelectorAll("path, clipPath, svg")
+    ?.querySelectorAll("path, clipPath, svg")
     .forEach(el => el.remove());
-  byId("coas").innerHTML = ""; // remove auto-generated emblems
+
+  // remove auto-generated emblems
+  if (byId("coas")) byId("coas")!.innerHTML = "";
+
   notes = [];
   rulers = new Rulers();
+
   unfog();
 }
 
diff --git a/src/scripts/reGraph.ts b/src/scripts/reGraph.ts
index a1546487..25701084 100644
--- a/src/scripts/reGraph.ts
+++ b/src/scripts/reGraph.ts
@@ -5,9 +5,12 @@ import {UINT16_MAX} from "constants";
 import {createTypedArray} from "utils/arrayUtils";
 import {calculateVoronoi, getPackPolygon} from "utils/graphUtils";
 import {rn} from "utils/numberUtils";
+import {DISTANCE_FIELD, MIN_LAND_HEIGHT} from "config/generation";
+
+const {LAND_COAST, WATER_COAST, DEEPER_WATER} = DISTANCE_FIELD;
 
 // recalculate Voronoi Graph to pack cells
-export function reGraph() {
+export function reGraph(grid: IGrid) {
   TIME && console.time("reGraph");
   const {cells: gridCells, points, features} = grid;
   const newCells: {p: TPoints; g: number[]; h: number[]} = {p: [], g: [], h: []}; // store new data
@@ -16,14 +19,18 @@ export function reGraph() {
   for (const i of gridCells.i) {
     const height = gridCells.h[i];
     const type = gridCells.t[i];
-    if (height < 20 && type !== -1 && type !== -2) continue; // exclude all deep ocean points
-    if (type === -2 && (i % 4 === 0 || features[gridCells.f[i]].type === "lake")) continue; // exclude non-coastal lake points
+    if (height < MIN_LAND_HEIGHT && type !== WATER_COAST && type !== DEEPER_WATER) continue; // exclude all deep ocean points
+
+    const feature = features[gridCells.f[i]];
+    const isLake = feature && feature.type === "lake";
+
+    if (type === DEEPER_WATER && (i % 4 === 0 || isLake)) continue; // exclude non-coastal lake points
     const [x, y] = points[i];
 
     addNewPoint(i, x, y, height);
 
     // add additional points for cells along coast
-    if (type === 1 || type === -1) {
+    if (type === LAND_COAST || type === WATER_COAST) {
       if (gridCells.b[i]) continue; // not for near-border cells
       gridCells.c[i].forEach(e => {
         if (i > e) return;
@@ -55,7 +62,7 @@ export function reGraph() {
   pack.cells.p = newCells.p;
   pack.cells.g = createTypedArray({maxValue: grid.points.length, from: newCells.g});
   pack.cells.q = d3.quadtree(newCells.p.map(([x, y], i) => [x, y, i]));
-  pack.cells.h = createTypedArray({maxValue: 100, from: newCells.h});
+  pack.cells.h = new Uint8Array(newCells.h);
   pack.cells.area = createTypedArray({maxValue: UINT16_MAX, from: pack.cells.i}).map(getCellArea);
 
   TIME && console.timeEnd("reGraph");
diff --git a/src/types/grid.d.ts b/src/types/grid.d.ts
index 6dcf39fd..c6417078 100644
--- a/src/types/grid.d.ts
+++ b/src/types/grid.d.ts
@@ -5,16 +5,26 @@ interface IGrid extends IGraph {
   spacing: number;
   boundary: TPoints;
   points: TPoints;
-  cells: IGridCells;
+  cells: IGraphCells & IGridCells;
   features: TGridFeatures;
 }
 
-interface IGridCells extends IGraphCells {
-  h: UintArray; // heights, [0, 100], see MIN_LAND_HEIGHT constant
+interface IGridCells {
+  h: Uint8Array; // heights, [0, 100], see MIN_LAND_HEIGHT constant
   t: Int8Array; // see DISTANCE_FIELD enum
   f: Uint16Array; // feature id, see IGridFeature
-  temp: UintArray; // temparature in Celsius
-  prec: UintArray; // precipitation in inner units
+  temp: Int8Array; // temparature in Celsius
+  prec: Uint8Array; // precipitation in inner units
+}
+
+interface IGridBase extends IGrid {
+  cells: IGraphCells & Partial<IGridCells>;
+  features?: TGridFeatures;
+}
+
+interface IGridWithHeights extends IGrid {
+  cells: IGraphCells & Partial<IGridCells> & {h: Uint8Array};
+  features?: TGridFeatures;
 }
 
 type TGridFeatures = [0, ...IGridFeature[]];
diff --git a/src/types/overrides.d.ts b/src/types/overrides.d.ts
index c7458943..b0b099c2 100644
--- a/src/types/overrides.d.ts
+++ b/src/types/overrides.d.ts
@@ -6,16 +6,23 @@ interface Navigator {
 
 interface Window {
   mapCoordinates: IMapCoordinates;
-  $: typeof $;
+  $: typeof $; // jQuery
+
   // untyped IIFE modules
-  Biomes: typeof Biomes;
-  Names: typeof Names;
-  ThreeD: typeof ThreeD;
-  ReliefIcons: typeof ReliefIcons;
-  Zoom: typeof Zoom;
-  Lakes: typeof Lakes;
-  HeightmapGenerator: typeof HeightmapGenerator;
-  OceanLayers: typeof OceanLayers;
+  Biomes: any;
+  Names: any;
+  ThreeD: any;
+  ReliefIcons: any;
+  Zoom: any;
+  Lakes: any;
+  HeightmapGenerator: any;
+  OceanLayers: any;
+  Rivers: any;
+  Cultures: any;
+  BurgsAndStates: any;
+  Religions: any;
+  Military: any;
+  Markers: any;
 }
 
 interface Node {
diff --git a/src/types/pack.d.ts b/src/types/pack.d.ts
index b3728fd9..a80e7324 100644
--- a/src/types/pack.d.ts
+++ b/src/types/pack.d.ts
@@ -11,7 +11,7 @@ interface IPack extends IGraph {
 
 interface IPackCells extends IGraphCells {
   p: TPoints; // cell center points
-  h: UintArray; // heights, [0, 100], see MIN_LAND_HEIGHT constant
+  h: Uint8Array; // heights, [0, 100], see MIN_LAND_HEIGHT constant
   t: Int8Array; // see DISTANCE_FIELD enum
   f: Uint16Array; // feature id, see TPackFeature
   g: UintArray;