Time and dates

Measures of Time

The base unit of time is the second (s).
Time is usually recorded in minutes (min), hours (h), days, weeks, months, or years.
Key conversions include:
- 60s = 1min,
- 60min = 1h,
- 24h = 1 day,
- 7 days = 1 week.
A month can vary between 28 to 31 days. Most years have 365 days, but every fourth year (a leap year) has 366 days with an additional day in February.
Important to know that 1 year = 52 weeks approximately but this is less accurate since a year can be 365 or 366 days.

There are different systems of time-keeping based on different cultural practices or scientific methods. Most commonly used is the 24-hour clock.
In a 24-hour clock, the day runs from midnight to midnight and is divided into 24 hours, from 0 to 23.
Another common system is the 12-hour clock. This divides the 24 hours into two periods lasting 12 hours each. The first 12-hour period is designated as am. The second 12-hour period is designated as pm.

Dates are usually expressed in a day, month and year format.
When writing out the date, it is standard practice in the UK to put the day first, followed by the month, and then the year. For example, 15th April 2003 is often written as 15/04/2003.
It is important to know the number of days in each month to correctly calculate the passing of time. Remember the rhyme: “Thirty days hath September, April, June, and November. All the rest have thirty-one, Excepting February alone…”

The Earth is divided into 24 time zones. Each time zone represents a geographic region in which the same standard time is used.
The reference point for all time zones is the Greenwich Mean Time (GMT), situated at the Prime Meridian (0° longitude). As you move east from the Prime Meridian, every 15 degrees represents a new time zone that is one hour ahead of GMT. Conversely, as you move west every 15 degrees represents a time zone that is one hour behind GMT.
During the summer months, some countries adjust their clocks forward by one hour to maximise daylight. This is known as Daylight Saving Time (DST). It’s important to consider this while calculating time in different zones.