diff --git a/ApiCore-Backend/src/auth/guards/permissions.guard.ts b/ApiCore-Backend/src/auth/guards/permissions.guard.ts
index ae34c1c..ba35c12 100644
--- a/ApiCore-Backend/src/auth/guards/permissions.guard.ts
+++ b/ApiCore-Backend/src/auth/guards/permissions.guard.ts
@@ -10,10 +10,14 @@ interface RequestWithUser {
 }
 
 /**
- * Runs alongside the legacy RolesGuard during the RBAC migration: routes
- * without @RequirePermission are untouched here (still governed solely by
- * @Roles), routes with it are enforced against the caller's live
- * permission set. Both guards must pass for a request to proceed.
+ * Fail-open by decorator absence: a route with no @RequirePermission is
+ * allowed through untouched (any authenticated user can reach it), only
+ * routes that carry the decorator are enforced against the caller's live
+ * permission set. There is no default-deny here, so
+ * test/authorization-coverage.e2e-spec.ts — which fails the build if any
+ * non-public route lacks a catalog-valid @RequirePermission — is the sole
+ * safety net for "someone added a route and forgot the decorator", not a
+ * defense-in-depth nicety.
  */
 @Injectable()
 export class PermissionsGuard implements CanActivate {
diff --git a/ApiCore-Backend/src/auth/permissions/permission-resolver.service.spec.ts b/ApiCore-Backend/src/auth/permissions/permission-resolver.service.spec.ts
new file mode 100644
index 0000000..1a7da8a
--- /dev/null
+++ b/ApiCore-Backend/src/auth/permissions/permission-resolver.service.spec.ts
@@ -0,0 +1,134 @@
+import { PermissionResolverService } from './permission-resolver.service';
+import { PrismaService } from '../../prisma/prisma.service';
+
+describe('PermissionResolverService', () => {
+  let resolver: PermissionResolverService;
+  let prisma: { user: { findUnique: jest.Mock } };
+
+  function activeUserWithPermissions(...keys: string[]) {
+    return {
+      isActive: true,
+      role: {
+        status: 'ACTIVE',
+        permissions: keys.map((key) => ({ permission: { key } })),
+      },
+    };
+  }
+
+  beforeEach(() => {
+    prisma = { user: { findUnique: jest.fn() } };
+    resolver = new PermissionResolverService(
+      prisma as unknown as PrismaService,
+    );
+  });
+
+  it('returns the granted permission keys for an active user with an active role', async () => {
+    prisma.user.findUnique.mockResolvedValue(
+      activeUserWithPermissions('colonies:read', 'tasks:create'),
+    );
+
+    const permissions = await resolver.getPermissions('user-1');
+
+    expect(Array.from(permissions).sort()).toEqual(
+      ['colonies:read', 'tasks:create'].sort(),
+    );
+  });
+
+  it('returns no permissions for a deactivated user, even if their role is active', async () => {
+    prisma.user.findUnique.mockResolvedValue({
+      isActive: false,
+      role: {
+        status: 'ACTIVE',
+        permissions: [{ permission: { key: 'colonies:read' } }],
+      },
+    });
+
+    const permissions = await resolver.getPermissions('user-1');
+
+    expect(permissions.size).toBe(0);
+  });
+
+  it('returns no permissions when the role itself is deactivated', async () => {
+    prisma.user.findUnique.mockResolvedValue({
+      isActive: true,
+      role: {
+        status: 'INACTIVE',
+        permissions: [{ permission: { key: 'colonies:read' } }],
+      },
+    });
+
+    const permissions = await resolver.getPermissions('user-1');
+
+    expect(permissions.size).toBe(0);
+  });
+
+  it('returns no permissions when the user does not exist', async () => {
+    prisma.user.findUnique.mockResolvedValue(null);
+
+    const permissions = await resolver.getPermissions('missing');
+
+    expect(permissions.size).toBe(0);
+  });
+
+  it('caches the result and does not re-query within the TTL', async () => {
+    prisma.user.findUnique.mockResolvedValue(
+      activeUserWithPermissions('colonies:read'),
+    );
+
+    await resolver.getPermissions('user-1');
+    await resolver.getPermissions('user-1');
+
+    expect(prisma.user.findUnique).toHaveBeenCalledTimes(1);
+  });
+
+  it('re-queries after invalidateUser', async () => {
+    prisma.user.findUnique.mockResolvedValue(
+      activeUserWithPermissions('colonies:read'),
+    );
+
+    await resolver.getPermissions('user-1');
+    resolver.invalidateUser('user-1');
+    await resolver.getPermissions('user-1');
+
+    expect(prisma.user.findUnique).toHaveBeenCalledTimes(2);
+  });
+
+  it('re-queries after invalidateAll', async () => {
+    prisma.user.findUnique.mockResolvedValue(
+      activeUserWithPermissions('colonies:read'),
+    );
+
+    await resolver.getPermissions('user-1');
+    resolver.invalidateAll();
+    await resolver.getPermissions('user-1');
+
+    expect(prisma.user.findUnique).toHaveBeenCalledTimes(2);
+  });
+
+  describe('hasAny', () => {
+    it('returns true when the user holds at least one of the requested keys', async () => {
+      prisma.user.findUnique.mockResolvedValue(
+        activeUserWithPermissions('colonies:read'),
+      );
+
+      await expect(
+        resolver.hasAny('user-1', ['tasks:create', 'colonies:read']),
+      ).resolves.toBe(true);
+    });
+
+    it('returns false when the user holds none of the requested keys', async () => {
+      prisma.user.findUnique.mockResolvedValue(
+        activeUserWithPermissions('colonies:read'),
+      );
+
+      await expect(resolver.hasAny('user-1', ['tasks:create'])).resolves.toBe(
+        false,
+      );
+    });
+
+    it('returns true when no keys are required', async () => {
+      await expect(resolver.hasAny('user-1', [])).resolves.toBe(true);
+      expect(prisma.user.findUnique).not.toHaveBeenCalled();
+    });
+  });
+});
diff --git a/ApiCore-Backend/src/auth/permissions/permission-resolver.service.ts b/ApiCore-Backend/src/auth/permissions/permission-resolver.service.ts
index 5da9013..e17acaa 100644
--- a/ApiCore-Backend/src/auth/permissions/permission-resolver.service.ts
+++ b/ApiCore-Backend/src/auth/permissions/permission-resolver.service.ts
@@ -60,6 +60,7 @@ export class PermissionResolverService {
     const user = await this.prisma.user.findUnique({
       where: { id: userId },
       select: {
+        isActive: true,
         role: {
           select: {
             status: true,
@@ -70,7 +71,7 @@ export class PermissionResolverService {
         },
       },
     });
-    if (!user || user.role.status !== 'ACTIVE') {
+    if (!user || !user.isActive || user.role.status !== 'ACTIVE') {
       return new Set();
     }
     return new Set(user.role.permissions.map((grant) => grant.permission.key));
diff --git a/ApiCore-Backend/src/users/users.service.spec.ts b/ApiCore-Backend/src/users/users.service.spec.ts
index 461d428..ba747c8 100644
--- a/ApiCore-Backend/src/users/users.service.spec.ts
+++ b/ApiCore-Backend/src/users/users.service.spec.ts
@@ -2,6 +2,7 @@ import { ConflictException, NotFoundException } from '@nestjs/common';
 import { UsersService } from './users.service';
 import { PrismaService } from '../prisma/prisma.service';
 import { AuditLogService } from '../audit/audit-log.service';
+import { PermissionResolverService } from '../auth/permissions/permission-resolver.service';
 
 describe('UsersService', () => {
   let usersService: UsersService;
@@ -11,18 +12,32 @@ describe('UsersService', () => {
       findUnique: jest.Mock;
       create: jest.Mock;
       update: jest.Mock;
+      count: jest.Mock;
     };
     role: {
       findUnique: jest.Mock;
     };
   };
   let auditLog: { record: jest.Mock };
+  let permissionResolver: {
+    invalidateUser: jest.Mock;
+    invalidateAll: jest.Mock;
+  };
 
   const staffRole = {
     id: 'role-staff',
     key: 'STAFF',
     name: 'Mitarbeiter',
     status: 'ACTIVE',
+    isSystem: false,
+  };
+
+  const adminRole = {
+    id: 'role-admin',
+    key: 'ADMIN',
+    name: 'Administrator',
+    status: 'ACTIVE',
+    isSystem: true,
   };
 
   const existingUser = {
@@ -37,6 +52,14 @@ describe('UsersService', () => {
     deactivatedAt: null,
   };
 
+  const adminUser = {
+    ...existingUser,
+    id: 'user-admin',
+    email: 'admin@example.com',
+    roleId: adminRole.id,
+    role: adminRole,
+  };
+
   beforeEach(() => {
     prisma = {
       user: {
@@ -44,15 +67,21 @@ describe('UsersService', () => {
         findUnique: jest.fn(),
         create: jest.fn(),
         update: jest.fn(),
+        count: jest.fn(),
       },
       role: {
         findUnique: jest.fn().mockResolvedValue(staffRole),
       },
     };
     auditLog = { record: jest.fn().mockResolvedValue(undefined) };
+    permissionResolver = {
+      invalidateUser: jest.fn(),
+      invalidateAll: jest.fn(),
+    };
     usersService = new UsersService(
       prisma as unknown as PrismaService,
       auditLog as unknown as AuditLogService,
+      permissionResolver as unknown as PermissionResolverService,
     );
   });
 
@@ -151,7 +180,7 @@ describe('UsersService', () => {
     );
   });
 
-  it('deactivate sets isActive to false and records an audit entry', async () => {
+  it('deactivate sets isActive to false, invalidates the permission cache, and records an audit entry', async () => {
     prisma.user.findUnique.mockResolvedValue(existingUser);
     prisma.user.update.mockResolvedValue({
       ...existingUser,
@@ -163,11 +192,39 @@ describe('UsersService', () => {
 
     expect(result.isActive).toBe(false);
     expect(result.deactivatedAt).not.toBeNull();
+    expect(permissionResolver.invalidateUser).toHaveBeenCalledWith(
+      existingUser.id,
+    );
     expect(auditLog.record).toHaveBeenCalledWith(
       expect.objectContaining({ entityType: 'User', action: 'DEACTIVATE' }),
     );
   });
 
+  it('deactivate throws ConflictException when deactivating the last active user of a system role', async () => {
+    prisma.user.findUnique.mockResolvedValue(adminUser);
+    prisma.user.count.mockResolvedValue(1);
+
+    await expect(usersService.deactivate(adminUser.id)).rejects.toBeInstanceOf(
+      ConflictException,
+    );
+    expect(prisma.user.update).not.toHaveBeenCalled();
+    expect(permissionResolver.invalidateUser).not.toHaveBeenCalled();
+  });
+
+  it('deactivate succeeds for a system-role user when another active user shares that role', async () => {
+    prisma.user.findUnique.mockResolvedValue(adminUser);
+    prisma.user.count.mockResolvedValue(2);
+    prisma.user.update.mockResolvedValue({
+      ...adminUser,
+      isActive: false,
+      deactivatedAt: new Date(),
+    });
+
+    const result = await usersService.deactivate(adminUser.id);
+
+    expect(result.isActive).toBe(false);
+  });
+
   it('activate throws ConflictException when already active', async () => {
     prisma.user.findUnique.mockResolvedValue(existingUser);
     await expect(usersService.activate(existingUser.id)).rejects.toBeInstanceOf(
@@ -175,7 +232,7 @@ describe('UsersService', () => {
     );
   });
 
-  it('activate sets isActive to true and clears deactivatedAt', async () => {
+  it('activate sets isActive to true, invalidates the permission cache, and clears deactivatedAt', async () => {
     prisma.user.findUnique.mockResolvedValue({
       ...existingUser,
       isActive: false,
@@ -191,8 +248,46 @@ describe('UsersService', () => {
 
     expect(result.isActive).toBe(true);
     expect(result.deactivatedAt).toBeNull();
+    expect(permissionResolver.invalidateUser).toHaveBeenCalledWith(
+      existingUser.id,
+    );
     expect(auditLog.record).toHaveBeenCalledWith(
       expect.objectContaining({ entityType: 'User', action: 'UPDATE' }),
     );
   });
+
+  it('update invalidates the permission cache when the role changes', async () => {
+    prisma.user.findUnique.mockResolvedValue(existingUser);
+    prisma.user.update.mockResolvedValue({
+      ...existingUser,
+      roleId: adminRole.id,
+      role: adminRole,
+    });
+
+    await usersService.update(existingUser.id, { roleId: adminRole.id });
+
+    expect(permissionResolver.invalidateUser).toHaveBeenCalledWith(
+      existingUser.id,
+    );
+  });
+
+  it('update does not touch the permission cache when the role is unchanged', async () => {
+    prisma.user.findUnique.mockResolvedValue(existingUser);
+    prisma.user.update.mockResolvedValue({ ...existingUser, name: 'Renamed' });
+
+    await usersService.update(existingUser.id, { name: 'Renamed' });
+
+    expect(permissionResolver.invalidateUser).not.toHaveBeenCalled();
+  });
+
+  it('update throws ConflictException when reassigning the last active user away from a system role', async () => {
+    prisma.user.findUnique.mockResolvedValue(adminUser);
+    prisma.role.findUnique.mockResolvedValue(staffRole);
+    prisma.user.count.mockResolvedValue(1);
+
+    await expect(
+      usersService.update(adminUser.id, { roleId: staffRole.id }),
+    ).rejects.toBeInstanceOf(ConflictException);
+    expect(prisma.user.update).not.toHaveBeenCalled();
+  });
 });
diff --git a/ApiCore-Backend/src/users/users.service.ts b/ApiCore-Backend/src/users/users.service.ts
index 1177ed8..1a76811 100644
--- a/ApiCore-Backend/src/users/users.service.ts
+++ b/ApiCore-Backend/src/users/users.service.ts
@@ -6,6 +6,7 @@ import {
 import * as bcrypt from 'bcryptjs';
 import { PrismaService } from '../prisma/prisma.service';
 import { AuditLogService } from '../audit/audit-log.service';
+import { PermissionResolverService } from '../auth/permissions/permission-resolver.service';
 import { Prisma } from '../../generated/prisma';
 import { CreateUserDto } from './dto/create-user.dto';
 import { UpdateUserDto } from './dto/update-user.dto';
@@ -35,6 +36,7 @@ export class UsersService {
   constructor(
     private readonly prisma: PrismaService,
     private readonly auditLog: AuditLogService,
+    private readonly permissionResolver: PermissionResolverService,
   ) {}
 
   private toSummary(user: UserWithRole): UserSummary {
@@ -61,6 +63,32 @@ export class UsersService {
     }
   }
 
+  /**
+   * Blocks removing (by deactivation or role reassignment) the last active
+   * user still holding a system role (ADMIN). Without this, an operator
+   * could lock the app out of user/role management entirely, with no
+   * self-service recovery: prisma/seed.ts skips seeding once a user with
+   * its configured email already exists, so it cannot restore access to a
+   * merely demoted/deactivated account.
+   */
+  private async assertNotLastSystemRoleUser(userId: string): Promise<void> {
+    const user = await this.prisma.user.findUnique({
+      where: { id: userId },
+      select: { roleId: true, role: { select: { isSystem: true } } },
+    });
+    if (!user || !user.role.isSystem) {
+      return;
+    }
+    const activeCount = await this.prisma.user.count({
+      where: { roleId: user.roleId, isActive: true },
+    });
+    if (activeCount <= 1) {
+      throw new ConflictException(
+        'Cannot remove the last active user holding a system role',
+      );
+    }
+  }
+
   async findAll(): Promise<UserSummary[]> {
     const users = await this.prisma.user.findMany({
       ...USER_WITH_ROLE,
@@ -123,9 +151,13 @@ export class UsersService {
     actingUserId?: string,
   ): Promise<UserSummary> {
     const before = await this.findById(id);
+    const roleChanged = Boolean(dto.roleId) && dto.roleId !== before.roleId;
     if (dto.roleId) {
       await this.assertActiveRole(dto.roleId);
     }
+    if (roleChanged) {
+      await this.assertNotLastSystemRoleUser(id);
+    }
     const user = await this.prisma.user.update({
       where: { id },
       data: {
@@ -134,6 +166,9 @@ export class UsersService {
       },
       ...USER_WITH_ROLE,
     });
+    if (roleChanged) {
+      this.permissionResolver.invalidateUser(id);
+    }
     await this.auditLog.record({
       entityType: 'User',
       entityId: id,
@@ -147,11 +182,13 @@ export class UsersService {
 
   async deactivate(id: string, actingUserId?: string): Promise<UserSummary> {
     const before = await this.findById(id);
+    await this.assertNotLastSystemRoleUser(id);
     const user = await this.prisma.user.update({
       where: { id },
       data: { isActive: false, deactivatedAt: new Date() },
       ...USER_WITH_ROLE,
     });
+    this.permissionResolver.invalidateUser(id);
     await this.auditLog.record({
       entityType: 'User',
       entityId: id,
@@ -173,6 +210,7 @@ export class UsersService {
       data: { isActive: true, deactivatedAt: null },
       ...USER_WITH_ROLE,
     });
+    this.permissionResolver.invalidateUser(id);
     await this.auditLog.record({
       entityType: 'User',
       entityId: id,
diff --git a/ApiCore-Backend/src/weather/weather.service.spec.ts b/ApiCore-Backend/src/weather/weather.service.spec.ts
index 0ae37f0..f0913f0 100644
--- a/ApiCore-Backend/src/weather/weather.service.spec.ts
+++ b/ApiCore-Backend/src/weather/weather.service.spec.ts
@@ -101,6 +101,20 @@ describe('WeatherService', () => {
         weatherService.getWeather('apiary-1'),
       ).rejects.toBeInstanceOf(BadRequestException);
     });
+
+    it('throws BadRequestException instead of hanging when the request times out or the network fails', async () => {
+      prisma.apiary.findUnique.mockResolvedValue({
+        latitude: 52.5,
+        longitude: 13.4,
+      });
+      fetchMock.mockRejectedValue(
+        new DOMException('The operation was aborted', 'TimeoutError'),
+      );
+
+      await expect(
+        weatherService.getWeather('apiary-1'),
+      ).rejects.toBeInstanceOf(BadRequestException);
+    });
   });
 
   describe('getTrachtprognose', () => {
@@ -179,6 +193,22 @@ describe('WeatherService', () => {
       expect(result.season).toBe('Frühtracht');
     });
 
+    it('returns UNBEKANNT during bloom season when there is no usable temperature data', async () => {
+      mockToday('2026-06-10');
+      prisma.apiary.findUnique.mockResolvedValue({
+        latitude: 52.5,
+        longitude: 13.4,
+      });
+      fetchMock.mockResolvedValue(
+        new Response(JSON.stringify(openMeteoResponse([])), { status: 200 }),
+      );
+
+      const result = await weatherService.getTrachtprognose('apiary-1');
+
+      expect(result.rating).toBe('UNBEKANNT');
+      expect(result.season).toBe('Sommertracht');
+    });
+
     it('includes the historical average yield when past harvests exist for the same month', async () => {
       mockToday('2026-06-10');
       prisma.apiary.findUnique.mockResolvedValue({
diff --git a/ApiCore-Backend/src/weather/weather.service.ts b/ApiCore-Backend/src/weather/weather.service.ts
index 63ba5e9..3ebad3e 100644
--- a/ApiCore-Backend/src/weather/weather.service.ts
+++ b/ApiCore-Backend/src/weather/weather.service.ts
@@ -9,6 +9,7 @@ const OPEN_METEO_FORECAST_URL = 'https://api.open-meteo.com/v1/forecast';
 const PAST_DAYS = 14;
 const FORECAST_DAYS = 7;
 const RECENT_WINDOW_DAYS = 7;
+const FETCH_TIMEOUT_MS = 8_000;
 const GOOD_TEMP_THRESHOLD_C = 18;
 const GOOD_PRECIPITATION_THRESHOLD_MM = 15;
 const POOR_TEMP_THRESHOLD_C = 12;
@@ -26,7 +27,7 @@ export interface ApiaryWeather {
 }
 
 export type TrachtprognoseRating =
-  'GUT' | 'MAESSIG' | 'SCHWACH' | 'KEINE_TRACHT';
+  'GUT' | 'MAESSIG' | 'SCHWACH' | 'KEINE_TRACHT' | 'UNBEKANNT';
 
 export interface Trachtprognose {
   rating: TrachtprognoseRating;
@@ -100,7 +101,14 @@ export class WeatherService {
     url.searchParams.set('forecast_days', String(FORECAST_DAYS));
     url.searchParams.set('timezone', 'auto');
 
-    const response = await fetch(url);
+    let response: Response;
+    try {
+      response = await fetch(url, {
+        signal: AbortSignal.timeout(FETCH_TIMEOUT_MS),
+      });
+    } catch {
+      throw new BadRequestException('Wetterdaten konnten nicht geladen werden');
+    }
     if (!response.ok) {
       throw new BadRequestException('Wetterdaten konnten nicht geladen werden');
     }
@@ -178,7 +186,7 @@ export class WeatherService {
       0,
     );
 
-    let rating: TrachtprognoseRating = 'MAESSIG';
+    let rating: TrachtprognoseRating = 'UNBEKANNT';
     if (avgTempMax === null) {
       reasoning.push('Keine ausreichenden Wetterdaten für eine Einschätzung.');
     } else if (
@@ -198,6 +206,7 @@ export class WeatherService {
         `Kühles oder nasses Wetter der letzten 7 Tage (Ø ${avgTempMax.toFixed(1)}°C, ${totalPrecipitation.toFixed(0)} mm Niederschlag) schränkt Bienenflug ein.`,
       );
     } else {
+      rating = 'MAESSIG';
       reasoning.push(
         `Durchwachsenes Wetter der letzten 7 Tage (Ø ${avgTempMax.toFixed(1)}°C, ${totalPrecipitation.toFixed(0)} mm Niederschlag).`,
       );
diff --git a/ApiCore-Frontend/src/app/(app)/apiaries/[id]/weather-card.tsx b/ApiCore-Frontend/src/app/(app)/apiaries/[id]/weather-card.tsx
index ff89c31..e1a2a8c 100644
--- a/ApiCore-Frontend/src/app/(app)/apiaries/[id]/weather-card.tsx
+++ b/ApiCore-Frontend/src/app/(app)/apiaries/[id]/weather-card.tsx
@@ -12,6 +12,7 @@ const RATING_LABELS: Record<TrachtprognoseRating, string> = {
   MAESSIG: "Mäßige Tracht",
   SCHWACH: "Schwache Tracht",
   KEINE_TRACHT: "Keine Tracht",
+  UNBEKANNT: "Prognose nicht möglich",
 };
 
 const RATING_VARIANTS: Record<
@@ -22,6 +23,7 @@ const RATING_VARIANTS: Record<
   MAESSIG: "secondary",
   SCHWACH: "warning",
   KEINE_TRACHT: "outline",
+  UNBEKANNT: "outline",
 };
 
 function formatDayLabel(dateIso: string): string {
diff --git a/ApiCore-Frontend/src/lib/weather/types.ts b/ApiCore-Frontend/src/lib/weather/types.ts
index ac51cc7..bea98e5 100644
--- a/ApiCore-Frontend/src/lib/weather/types.ts
+++ b/ApiCore-Frontend/src/lib/weather/types.ts
@@ -9,7 +9,12 @@ export interface ApiaryWeather {
   daily: DailyWeather[];
 }
 
-export type TrachtprognoseRating = "GUT" | "MAESSIG" | "SCHWACH" | "KEINE_TRACHT";
+export type TrachtprognoseRating =
+  | "GUT"
+  | "MAESSIG"
+  | "SCHWACH"
+  | "KEINE_TRACHT"
+  | "UNBEKANNT";
 
 export interface Trachtprognose {
   rating: TrachtprognoseRating;