B
Evidence Grade B
Graded
accuracy verified by the review judge
Safe to Cite
Dated
23%
23% -- share of replies by send day for cold email (Wednesday) (2021-05)
Cold emails sent on Wednesday accounted for 23% of all replies received.
- Filtered to recipients with known time zones
Attribution:
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Lighthouse Research Team
Last verified:
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Source verified
Evidence graded
Value
23%
Unit
Percentage
Data Vintage
2021-05
Entity
Sample Size
600,000
Evidence Quality
B
Strong, reliable evidence
Sourced from a well-regarded research firm or industry leader with transparent methodology and a reasonably large sample.
Single source - not yet corroborated
Score breakdown
Extraction
95
Source Trust
60
Citation Chain
20
Independence
30
Methodology
45
Freshness
95
Source
CIENCE
Primary
Tier A
https://www.cience.com/blog/best-time-to-send-cold-emails-and-get-replies/ ↗
Source Article
Best Time to Send Cold Emails: 6 Data-Backed Findings | CIENCE
Last Refreshed: March 2026 with updated statistics and tool information.
The best time to send a cold email is 8 a.m. in the recipient's time zone (20% of all replies), on a Wednesday (23% of replies), with 87% of all replies arriving within the first 24 hours: based on CIENCE's analysis of 6 millio…
Original Research
CIENCE
· Original study ↗
Methodology
CIENCE Data Labs analysis of 600,000 rows with known time zones
Methodology documented
Segmentation
Industrymarketing
Cite this stat
Plain Text
cold email (Wednesday): 23% share of replies by send day. Source: CIENCE (2021-05). Via Lighthouse Intelligence -- https://lighthousedata.io/data/cold-email-wednesday-reply-share
HTML Embed
<blockquote cite="https://lighthousedata.io/data/cold-email-wednesday-reply-share" style="border-left:3px solid #2563eb;padding:12px 16px;margin:16px 0;font-family:system-ui,sans-serif;background:#f0f4ff;"><strong>23%</strong> -- share of replies by send day for cold email (Wednesday)<br><small>Source: CIENCE (2021-05) · <a href="https://lighthousedata.io/data/cold-email-wednesday-reply-share" target="_blank" rel="noopener">Lighthouse Intelligence</a></small></blockquote>
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