Trading sessions vs calendar days, twelve months through June 2026
Answered against 22 years of US equities and 12 years of US options data and published with the query that produced it. This result is stored as of 2026-08-01, from When Do Mutual Fund Trades Settle?.
| month | month_label | trading_sessions | calendar_days |
|---|---|---|---|
| 2025-07 | July 2025 | 22 | 31 |
| 2025-08 | August 2025 | 21 | 31 |
| 2025-09 | September 2025 | 21 | 30 |
| 2025-10 | October 2025 | 23 | 31 |
| 2025-11 | November 2025 | 19 | 30 |
| 2025-12 | December 2025 | 22 | 31 |
| 2026-01 | January 2026 | 20 | 31 |
| 2026-02 | February 2026 | 19 | 28 |
| 2026-03 | March 2026 | 22 | 31 |
| 2026-04 | April 2026 | 21 | 30 |
| 2026-05 | May 2026 | 20 | 31 |
| 2026-06 | June 2026 | 21 | 30 |
- Rows × columns
- 12 × 4
- Computed
- Completeness
- No missing values
- Source
- US exchange, SIP and OPRA market data
- Licence
- Strasmore terms · free, no signup
What each column holds
| Column | Type | Range | Notes |
|---|---|---|---|
month |
text | 12 distinct values (2025-07, 2025-08, 2025-09…) | |
month_label |
text | 12 distinct values (April 2026, August 2025, December 2025…) | |
trading_sessions |
number | 19 to 23 | |
calendar_days |
number | 28 to 31 |
Computed from Strasmore's warehouse of US exchange, SIP and OPRA market data. Equity prices are delayed; options greeks and implied volatility are end-of-day. This result is stored, not recomputed on load — it is exactly the numbers that were returned on , and the query below is what returned them.
Run it yourself
This is the exact query behind the result above. Change a ticker, a date or a column and run it against the warehouse — no account, no key. The no-signup tier is smaller than the one this page was computed on; a query that reaches past it comes back saying which plan runs it.
WITH sessions AS (
SELECT DISTINCT toDate(toTimeZone(window_start, 'America/New_York')) AS session_date
FROM global_markets.delayed_stocks_minute_aggs
WHERE ticker = 'SPY'
AND toDate(toTimeZone(window_start, 'America/New_York')) BETWEEN toDate('2025-07-01') AND toDate('2026-06-30')
AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
+ toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959
)
SELECT formatDateTime(toStartOfMonth(session_date), '%Y-%m') AS month,
formatDateTimeInJodaSyntax(toStartOfMonth(session_date), 'MMMM yyyy') AS month_label,
count() AS trading_sessions,
toDayOfMonth(toLastDayOfMonth(session_date)) AS calendar_days
FROM sessions
GROUP BY month, month_label, calendar_days
ORDER BY month
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