SPY overnight gaps by weekday: every session, January 2024 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 2026-07-26, from Why Do Stocks Gap Up or Down Overnight?.
| weekday | sessions | avg_abs_gap_pct | p90_abs_gap_pct |
|---|---|---|---|
| Monday | 119 | 0.52 | 1.11 |
| Tuesday | 131 | 0.36 | 0.73 |
| Wednesday | 127 | 0.39 | 0.92 |
| Thursday | 123 | 0.45 | 0.91 |
| Friday | 125 | 0.39 | 0.88 |
- Rows × columns
- 5 × 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 |
|---|---|---|---|
weekday |
text | 5 distinct values (Friday, Monday, Thursday…) | |
sessions |
number | 119 to 131 | |
avg_abs_gap_pct |
number | 0.36 to 0.52 | percent |
p90_abs_gap_pct |
number | 0.73 to 1.11 | percent |
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.
SELECT ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'][dow] AS weekday,
count() AS sessions,
round(avg(abs(gap_pct)), 2) AS avg_abs_gap_pct,
round(quantileDeterministic(0.9)(abs(gap_pct), toUInt64(toYYYYMMDD(day))), 2) AS p90_abs_gap_pct
FROM (
SELECT day, toDayOfWeek(day) AS dow,
100 * (rth_open - prior_close) / prior_close AS gap_pct
FROM (
SELECT day, rth_open, lagInFrame(rth_close) OVER (ORDER BY day) AS prior_close
FROM (
SELECT toDate(toTimeZone(window_start, 'America/New_York')) AS day,
argMinIf(toFloat64(open), window_start, rth) AS rth_open,
argMaxIf(toFloat64(close), window_start, rth) AS rth_close
FROM (
SELECT window_start, open, close,
toTimeZone(window_start, 'America/New_York') >= toDateTime(concat(toString(toDate(toTimeZone(window_start, 'America/New_York'))), ' 09:30:00'), 'America/New_York')
AND toTimeZone(window_start, 'America/New_York') < toDateTime(concat(toString(toDate(toTimeZone(window_start, 'America/New_York'))), ' 16:00:00'), 'America/New_York') AS rth
FROM global_markets.delayed_stocks_minute_aggs
WHERE ticker = 'SPY'
AND window_start >= '2023-12-28 04:00:00'
AND window_start < '2026-07-01 08:00:00'
)
GROUP BY day
)
)
WHERE day >= '2024-01-01' AND prior_close > 0 AND isFinite(prior_close)
)
WHERE dow <= 5
GROUP BY dow
ORDER BY dow
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