1. Convert 21 December 20:50 UTC to IST.
- Add 5 hours to reach 22 December 01:50.
- Add 30 minutes to reach 02:20.
- The time-zone conversion crosses midnight, so the local date changes.
Science · Suggested Classes 5–8
December Solstice 2026: Date, Daylight Graph & Activity
The same solstice happens on 21 December in UTC and 22 December in India. It is one event; the clock and calendar labels differ by location.
Start here
The December 2026 solstice occurs at 20:50 UTC on 21 December, according to the US Naval Observatory table. That is 02:20 IST on 22 December.
Original BananaLearn guide · 7 November 2026
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Find a section, worked example or practice question
The confirmed moment and local dates
The US Naval Observatory’s 2026 seasons table gives the December solstice at 20:50 with timezone offset zero on 21 December. This guide expresses that minute as 20:50 UTC. Adding India’s 5 hours 30 minutes gives 02:20 IST on 22 December.
A solstice is one global astronomical moment, not a different event in each country. The local date depends on the time zone. Use the official source below before adding a city-specific clock time.
What the solstice marks
Around this point, the Northern Hemisphere is tilted away from the Sun and the Southern Hemisphere towards it. It corresponds to the northern winter and southern summer solstice.
“Shortest day” means the least daylight in the relevant seasonal sense, not a civil day shorter than 24 hours. Near polar regions, the sunrise/sunset pattern needs additional explanation.
Separate daylight from temperature
Daylight depends strongly on latitude and season. Temperature also depends on heat storage, weather, altitude and other conditions. The solstice need not be the coldest or hottest local day.
Nor is the earliest sunset necessarily on the solstice date. A daylight-duration investigation asks a different question from finding a single sunrise or sunset extreme.
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Use the fictional paired-town record
For this maths task only, Northern Town has sunrise/sunset pairs: 15 November 07:00–16:30; 15 December 07:30–16:00; 22 December 07:40–15:55. Southern Town has 05:45–19:15, 05:25–19:45 and 05:20–19:50 on the same dates.
These are invented practice records illustrating opposite seasonal tendencies, not observed readings or astronomical predictions for named towns. Calculate daylight by subtracting sunrise from sunset on each date.
Calculate hours and minutes accurately
Northern Town’s last record is 15:55−07:40=8 hours 15 minutes. Southern Town’s last record is 19:50−05:20=14 hours 30 minutes. Keep hours and minutes separate before converting to decimal hours.
8 hours 15 minutes is 8.25 hours, not 8.15. Fifteen minutes is one quarter of an hour. The distinction matters when placing values on a graph with decimal-hour units.
Graph the two trends on the same scale
Use dates on the horizontal axis and daylight duration in hours on the vertical axis. Northern values are 9.5,8.5,8.25; southern values are 13.5,14⅓,14.5. State that the data are fictional.
A shared vertical scale makes the durations comparable. The intervals between dates are unequal, so position the dates proportionally on a true time axis or label an equally spaced display as separate recorded dates rather than a rate graph.
Observe safely, or use supplied data
If a family wants a real extension, use a reputable local sunrise/sunset source and record its place, time zone and definitions. Do not look at the Sun to time an observation.
Compare like with like: changing town or source halfway through a record can create a false trend. Cloudiness changes what you see in the sky but does not by itself redefine the astronomical sunrise calculation.
Write a bounded conclusion
For the supplied data, say that Northern Town’s recorded daylight decreases while Southern Town’s increases over the selected dates. Connect that fictional comparison with the tilt model, without presenting the values as measurements.
A parent can ask which parts are official facts, which are calculations and which are invented practice data. Keeping those categories distinct is part of the lesson, not a detail to hide in a footnote.
See the reasoning
Worked examples and checks
2. Calculate daylight from 07:30 to 16:00.
- 07:30 to 15:30 is 8 hours.
- A further 30 minutes gives 8 hours 30 minutes.
- In decimal hours, that is 8.5.
3. Compare the final paired records.
- Northern daylight: 8 h 15 min. Southern: 14 h 30 min.
- Difference: 6 h 15 min.
- That comparison belongs to the fictional data, not all places in the two hemispheres.
Try, explain, check
12 questions with explained answers
Try each task before opening its explanation. These are original BananaLearn questions, not official exam or past-paper questions. Where several answers can work, the explanation gives the criteria.
What UTC date is the 2026 December solstice?
Check answer and reasoning
21 December 2026
The official table gives 20:50 at offset zero.What is that moment in IST?
Check answer and reasoning
22 December, 02:20 IST
Add 5 h 30 min.Are those different solstices?
Check answer and reasoning
No
They are different local labels for one moment.Which hemisphere has its summer solstice then?
Check answer and reasoning
Southern Hemisphere
It is tilted towards the Sun.Does shortest day mean fewer than 24 clock hours?
Check answer and reasoning
No
It refers to daylight duration.Convert 8 h 15 min to decimal hours.
Check answer and reasoning
8.25 h
15/60=0.25.Find the fictional northern daylight on 15 November.
Check answer and reasoning
9 h 30 min
16:30−07:00.Find fictional southern daylight on 15 December.
Check answer and reasoning
14 h 20 min
19:45−05:25.Are the town records real observations?
Check answer and reasoning
No
They are explicitly invented practice data.Must the solstice be the coldest local day?
Check answer and reasoning
No
Temperature depends on more than daylight on one date.What should a real record include?
Check answer and reasoning
Place, dates, source and time zone
These make the measurements comparable.Should unequal date intervals look equal on a true time axis?
Check answer and reasoning
No
Their horizontal distances should reflect elapsed time.
A checking record to use in your notebook
Copy these headings and fill them for one worked task, then for a fresh attempt. Use your own evidence rather than copying the model answer.
- Date and setting
- What is confirmed, and which example is fictional?
- Task and conditions
- Which rule, quantity, passage or clue is supplied?
- Plan or answer
- What will I calculate, say or change?
- Evidence
- How can another reader check the reasoning?
- Revision
- What would I change after a trial or rehearsal?
Choose the next useful step
Explore BananaLearn’s games, learning features and one-to-one tutoring. Maths is our priority; English and Science tutoring are also available. Bring a recent example of schoolwork when checking teaching fit.
Sources, level and update
Original BananaLearn explanations, examples, illustrations and practice. Source facts checked 7 November 2026. Suggested levels are learning guides, not a claim that every board or textbook uses the same sequence.
Event timing is calendar-backed. Search demand is a forecast unless a separately measured trend is stated. No official event theme, school programme or affiliation is implied.
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