At the time of creating the post, it was Friday 30th. For some reason, my calendar displays this day as Saturday:
<Calendar
style={{width: Dimensions.get('screen').width - 10}}
theme={{
selectedDayBackgroundColor: '#00adf5',
selectedDayTextColor: '#ffffff',
dotColor: '#00adf5',
}}
onDayPress={this.onDaySelect}
markedDates={this.state.markedDates}
markingType="single"
minDate={minDate}
maxDate={maxDate}
disableAllTouchEventsForDisabledDays={true}
/>

This is likely a UTC issue where you're local time is now "tomorrow" in UTC. You should set the current property to today's date string. In my own, I use it like this:
const date = new Date();
<Calendar
current={date.toLocaleDateString()}
... // other props
/>
@lostchopstik Thank you for your help, but It doesn't work for me :(
console.log(new Date().toLocaleDateString()); shows 10/31/2020 (current date). console.log(new Date()); also shows current date (Sat Oct 31 2020 10:41:14 GMT+0300 (Moscow Standard Time)), but in calendar I also see incorrect variant.

I have faced same issues. Please help me
@mparkhomenko Please added parameters firstDay={6}.
@jaiminp-nimblechapps It didn't help :(
Do you have other variants?
@mparkhomenko
Go to this file location
react-native-calenders -> src -> calendar -> header -> index.js
and changed
let weekDaysNames = weekDayNames(this.props.firstDay);
to
let weekDaysNames = weekDayNames(6);
I have faced the same issue
I have resolved this issue from the above solution
@jaiminp-nimblechapps thank you!!!
@mparkhomenko Glad to help!!!!
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
Most helpful comment
@mparkhomenko
Go to this file location
and changed
I have faced the same issue
I have resolved this issue from the above solution