True solar time · By city
True Solar Time in Toronto
Auspice ·
多伦多 · 真太阳时
In Toronto, true solar time runs 1 to 87 minutes behind the clock. Across every clock minute of 1980, 1990, 2000, 2010, 43.8% land in a different BaZi hour pillar once corrected (63.5% under daylight saving, 17.2% outside it), and 3.6% on a different day pillar.
How often does the hour pillar change in Toronto?
| Clock minutes whose hour pillar changes | 43.8% |
| Range across 1980, 1990, 2000, 2010 | 39.9% – 47.6% |
| During daylight saving | 63.5% |
| Outside daylight saving | 17.2% |
| Share of minutes under daylight saving | 57.5% |
| Clock minutes whose day pillar changes | 3.6% |
| Correction range | −87 … −1 min |
From the 40-city study on the main true-solar-time page: every clock minute of 1980, 1990, 2000, 2010 in the America/Toronto time zone at 79.38°W, converted to true solar time. Minutes are weighted equally, so this is a per-minute figure, not a per-birth one. Data: /data/solar-time-study.json (CC BY 4.0).
Why the clock and the sun disagree here
Toronto is at 79.38°W; its standard clock follows the 75°W meridian (UTC−5). The earth turns one degree every four minutes, so the longitude part of the correction is −18 minutes, the same every day of the year. The equation of time adds a seasonal swing of roughly −15 to +16 minutes. Daylight saving adds another −60 minutes whenever it is in force, which was 57.5% of clock minutes across the study years. That is why the rate under daylight saving (63.5%) is so much higher than outside it (17.2%).
Toronto's clock since 1940
A chart has to use the clock that was in force on the birth date, not today’s. The table below is read directly from the IANA time-zone database the calculator uses, so it lists exactly the offsets a chart for each period is computed with.
| From | Until | Clock | Longitude part | Note |
|---|---|---|---|---|
| already in use in 1940 | 28 April 1940 | UTC−5 | −18 min | — |
| 28 April 1940 | 30 September 1945 | UTC−4 | −78 min | clocks one hour ahead all year |
| 30 September 1945 | today | UTC−5 | −18 min | plus −60 min in daylight-saving months |
Dates are the local day the clock changed. The longitude part is what the correction would be from longitude alone on that clock.
Daylight-saving rules by year
| Years | Starts | Ends | Clock in summer |
|---|---|---|---|
| 1946–1948 | last Sunday of April | last Sunday of September | UTC−4 |
| 1949–1950 | last Sunday of April | last Sunday of November | UTC−4 |
| 1951–1956 | last Sunday of April | last Sunday of September | UTC−4 |
| 1957–1986 | last Sunday of April | last Sunday of October | UTC−4 |
| 1987–2006 | first Sunday of April | last Sunday of October | UTC−4 |
| 2007–2026 | second Sunday of March | first Sunday of November | UTC−4 |
A birth in the week around a change date is worth checking by hand: the same clock reading can fall on either side of it depending on the year.
Worked examples for Toronto
Each birth is cast twice by the same engine as the calculator: once on the clock time as written, once corrected to true solar time. Same-day convention for the late Rat hour.
1 July 1995, 11:20
A late-morning birth on Canada Day, under Eastern Daylight Time.
| By the clock | By the sun | |
|---|---|---|
| Time | 11:20 | 09:58 |
| Hour pillar | 戊午 (Horse hour) | 丁巳 (Snake hour) |
| Day pillar | 癸巳 | 癸巳 |
Correction −81 min: daylight saving −60, longitude −17, equation of time −4. The hour pillar changes from 戊午 (Horse hour) to 丁巳 (Snake hour).
1 December 1995, 11:20
The same clock time in December, on standard time.
| By the clock | By the sun | |
|---|---|---|
| Time | 11:20 | 11:12 |
| Hour pillar | 甲午 (Horse hour) | 甲午 (Horse hour) |
| Day pillar | 丙寅 | 丙寅 |
Correction −8 min: daylight saving 0, longitude −18, equation of time +10. The hour pillar stays 甲午 (Horse hour).
25 March 2012, 00:30
Half past midnight in late March, under daylight saving: a case where the date can move.
| By the clock | By the sun | |
|---|---|---|
| Time | 00:30 | 23:05 (24 March 2012) |
| Hour pillar | 丙子 (Rat hour) | 丙子 (Rat hour) |
| Day pillar | 乙酉 | 甲申 |
Correction −84 min: daylight saving −60, longitude −17, equation of time −7. The hour pillar stays 丙子 (Rat hour). By the sun the birth falls on 24 March 2012, and the day pillar moves from 乙酉 to 甲申. The corrected time is 5 minutes from a branch boundary, inside the 8-minute margin where the calculator marks the hour pillar as uncertain and shows both charts.
About the clock in Toronto
Toronto is at about 79.4°W, more than four degrees west of the 75.0°W meridian that Eastern Time follows. On standard time the sun peaks near 12:18 by the clock; add daylight saving and the gap is well over an hour for most of the year.
Ontario put its clocks forward for the war in April 1940 and left them there until September 1945. Seasonal daylight saving has run every year since 1946, and in 1949 and 1950 it ran as late as the end of November. Since 1987 the dates have matched those of the United States. In 2020 Ontario passed a law to stay on daylight time all year, but it only takes effect if Quebec and New York do the same, and it has not.
For a chart, the practical point is that Toronto is one of the North American cities where daylight saving and longitude pull in the same direction, which is why its rate is higher than New York’s despite sharing a time zone.
To apply all of this to one birth, enter the date, clock time and Toronto as the birthplace in the free BaZi calculator. It uses the same historical clock and the same three-part correction, shows the arithmetic, and needs no account. For why the correction exists at all, see true solar time in BaZi; to check whether another calculator applies it, try the three test birth times.
Other cities: true solar time in Singapore, true solar time in Kuala Lumpur, true solar time in Vancouver, true solar time in New York.