diff --git a/samples/react-rhythm-of-business-calendar/documentation/entities.md b/samples/react-rhythm-of-business-calendar/documentation/entities.md
index c906b1a58..a35c05456 100644
--- a/samples/react-rhythm-of-business-calendar/documentation/entities.md
+++ b/samples/react-rhythm-of-business-calendar/documentation/entities.md
@@ -29,8 +29,8 @@ import { User } from 'common';
 import { ListItemEntity } from 'common/sharepoint';
 
 interface IState {
-    int order;
-    User[] owners;
+    order: number;
+    owners: User[];
     // ... any other properties - these typically correspond with fields on the SharePoint list
 }
 
diff --git a/samples/react-rhythm-of-business-calendar/src/common/services/timezones/OnlineTimeZoneService.ts b/samples/react-rhythm-of-business-calendar/src/common/services/timezones/OnlineTimeZoneService.ts
index 890c637d3..eb0260f35 100644
--- a/samples/react-rhythm-of-business-calendar/src/common/services/timezones/OnlineTimeZoneService.ts
+++ b/samples/react-rhythm-of-business-calendar/src/common/services/timezones/OnlineTimeZoneService.ts
@@ -1,3 +1,4 @@
+import moment from 'moment-timezone';
 import { ICachingOptions } from '@pnp/odata';
 import { extractWebUrl, sp } from '@pnp/sp';
 import "@pnp/sp/regional-settings";
@@ -51,6 +52,7 @@ export class OnlineTimeZoneService implements ITimeZoneService {
 
     private _timeZones: TimeZone[];
     private _timeZonesBySharePointId: Map<number, TimeZone>;
+    private _localTimeZone: ITimeZone;
 
     public get timeZones(): ITimeZone[] {
         return this._timeZones;
@@ -60,6 +62,10 @@ export class OnlineTimeZoneService implements ITimeZoneService {
         return this._siteTimeZoneCache.get(sp.web.toUrl());
     }
 
+    public get localTimeZone(): ITimeZone {
+        return this._localTimeZone;
+    }
+
     public timeZoneFromId(id: number): ITimeZone {
         return this._timeZonesBySharePointId.get(id);
     }
@@ -84,6 +90,7 @@ export class OnlineTimeZoneService implements ITimeZoneService {
 
         this._timeZones = timeZoneResults.map(TimeZone.fromTimeZoneResult).filter(tz => tz.hasMomentMapping);
         this._timeZonesBySharePointId = arrayToMap(this._timeZones, tz => tz.id);
+        this._localTimeZone = this._timeZones.find(tz => tz.momentId === moment.tz.guess());
 
         this._siteTimeZoneCache.set(sp.web.toUrl(), siteTimeZone);
 
diff --git a/samples/react-rhythm-of-business-calendar/src/common/services/timezones/TimeZoneServiceDescriptor.ts b/samples/react-rhythm-of-business-calendar/src/common/services/timezones/TimeZoneServiceDescriptor.ts
index b14225193..33faf99f8 100644
--- a/samples/react-rhythm-of-business-calendar/src/common/services/timezones/TimeZoneServiceDescriptor.ts
+++ b/samples/react-rhythm-of-business-calendar/src/common/services/timezones/TimeZoneServiceDescriptor.ts
@@ -16,6 +16,7 @@ export interface ITimeZone {
 export interface ITimeZoneService extends IService {
     readonly timeZones: ITimeZone[];
     readonly siteTimeZone: ITimeZone;
+    readonly localTimeZone: ITimeZone;
     timeZoneFromId(id: number): ITimeZone;
     timeZoneForWeb(web?: IWeb): Promise<ITimeZone>;
 }
diff --git a/samples/react-rhythm-of-business-calendar/src/common/sharepoint/SPField.ts b/samples/react-rhythm-of-business-calendar/src/common/sharepoint/SPField.ts
index 60a339779..5499fb934 100644
--- a/samples/react-rhythm-of-business-calendar/src/common/sharepoint/SPField.ts
+++ b/samples/react-rhythm-of-business-calendar/src/common/sharepoint/SPField.ts
@@ -98,8 +98,8 @@ export const fromDateTime = <T>(row: T, fieldName: PropsOfType<T, Query_DateTime
     return value ? moment.tz(value, [moment.ISO_8601, sharepointDateTimeFormat], momentId) : null;
 };
 
-export const toDateTime = (dateTime: Moment): Update_DateTime => {
-    return dateTime ? dateTime.toISOString() : null;
+export const toDateTime = (dateTime: Moment, { momentId }: ITimeZone): Update_DateTime => {
+    return dateTime ? dateTime.tz(momentId, true).toISOString() : null;
 };
 
 export const toDateOnly = (dateTime: Moment): Update_DateTime => {
diff --git a/samples/react-rhythm-of-business-calendar/src/services/events/EventLoader.ts b/samples/react-rhythm-of-business-calendar/src/services/events/EventLoader.ts
index dad2f2536..91237335e 100644
--- a/samples/react-rhythm-of-business-calendar/src/services/events/EventLoader.ts
+++ b/samples/react-rhythm-of-business-calendar/src/services/events/EventLoader.ts
@@ -101,7 +101,7 @@ const getEventTypeValue = (event: Event) => {
     return 3; // 3 = cancelled this one occurrence of a series
 }
 
-const toUpdateListItem = (event: Event): IEventUpdateListItem => {
+const toUpdateListItem = (event: Event, siteTimeZone: ITimeZone): IEventUpdateListItem => {
     const { isNew, isAllDay, isRecurring, isSeriesMaster, isSeriesException } = event;
     return {
         Title: event.title,
@@ -109,20 +109,20 @@ const toUpdateListItem = (event: Event): IEventUpdateListItem => {
         Location: event.location,
         ContactsId: SPField.fromUsers(event.contacts),
         RefinerValuesId: SPField.toLookupMulti(event.refinerValues.get()),
-        EventDate: isAllDay ? SPField.toDateOnly(event.start) : SPField.toDateTime(event.start),
-        EndDate: isAllDay ? SPField.toDateOnly(event.end) : SPField.toDateTime(event.end),
+        EventDate: isAllDay ? SPField.toDateOnly(event.start) : SPField.toDateTime(event.start, siteTimeZone),
+        EndDate: isAllDay ? SPField.toDateOnly(event.end) : SPField.toDateTime(event.end, siteTimeZone),
         fAllDayEvent: event.isAllDay,
         IsConfidential: event.isConfidential,
         RestrictedToAccountsId: SPField.fromUsers(event.restrictedToAccounts),
         ModerationStatus: event.moderationStatus?.name || EventModerationStatus.Pending.name,
         ModeratorId: SPField.fromUser(event.moderator),
-        ModerationTimestamp: SPField.toDateTime(event.moderationTimestamp),
+        ModerationTimestamp: SPField.toDateTime(event.moderationTimestamp, siteTimeZone),
         ModerationMessage: event.moderationMessage,
         fRecurrence: SPField.tofRecurrence(isRecurring),
         EventType: getEventTypeValue(event),
         RecurrenceData: isSeriesMaster ? RecurrenceData.serialize(event.recurrence) : undefined,
         MasterSeriesItemID: isSeriesException ? event.seriesMaster.get()?.id : undefined,
-        RecurrenceID: isSeriesException ? SPField.toDateTime(event.recurrenceExceptionInstanceDate) : undefined,
+        RecurrenceID: isSeriesException ? SPField.toDateTime(event.recurrenceExceptionInstanceDate, siteTimeZone) : undefined,
         UID: isRecurring && isNew ? event.recurrenceUID?.toString() : undefined,
         Duration: event.duration.asSeconds()
     };
@@ -137,6 +137,6 @@ export class EventLoader extends PagedViewLoader<Event> {
 
     protected readonly extractReferencedUsers = (event: Event) => [...event.contacts, ...event.restrictedToAccounts, event.moderator];
     protected readonly toEntity = (row: IEventListItemResult, event: Event) => toEvent(row, event, this.timezones.siteTimeZone, this._refinerValueLoader, this._entitiesById);
-    protected readonly updateListItem = toUpdateListItem;
+    protected readonly updateListItem = (event: Event) => toUpdateListItem(event, this.timezones.siteTimeZone);
     protected readonly diagnosePersistError = (error: any) => ErrorHandler.is_412_PRECONDITION_FAILED(error) ? ErrorDiagnosis.Propogate : ErrorDiagnosis.Critical;
 }
\ No newline at end of file