Measured ICMP round-trip times from Seattle, USA to Johannesburg, South Africa: average 282.1 ms, min, max, jitter, and packet loss for this long-haul route.

🇺🇸 Seattle, USA (SEA) → 🇿🇦 Johannesburg, South Africa (JNB)

Measurement round: 2026-08-16T04:07:28Z.

In the 2026-08-16T04:07:28Z measurement round, ICMP echo requests from Seattle, USA to Johannesburg, South Africa averaged 282.1 ms round-trip, with a minimum of 273.42 ms and a maximum of 300.55 ms. The 50-sample run had no packet loss, and jitter was 5.55 ms.

For a geodesic distance of 16,502.7 km, the theoretical fiber floor is roughly 161.6 ms, so the observed average is about 75% above that floor. That overhead is consistent with a very long intercontinental path that cannot follow a straight great-circle line.

This route ranked 19th among the network's 19 measured outbound routes in the same round, making it the longest round-trip in the measured set. Its standard deviation is about 2.4% of the average RTT, however, which is tighter than the network's median ratio of 3.3%, so the path is very stable even though its absolute latency is high.

Latency Summary

Metric	Value
RTT	282.1 ms
Jitter	5.55 ms
Packet Loss	0%
Standard Fiber Floor	161.61 ms
Fiber Efficiency	57.3%
Latency Tier	High
Source Region	North America
Destination Region	Africa

Ping Measurement Series

The chart below renders the 50-sample ICMP echo measurement round for this route; an accessible table of every sample is included with the chart.

Ping series: SEA → JNB

50 ICMP echo samples at 100 ms intervals · round 2026-08-16T04:07:28Z · avg 282.1 ± 0.98 ms (SE)

Sample distribution: box = interquartile range (277.6–285.1 ms), median 280.3 ms · whiskers = min–max · diamond = round average · each dot is one measured sample.

How to read this chart

The shaded band spans the measured minimum to maximum RTT of all samples collected up to that point, and the thin line traces the running average. The final position therefore matches the round statistics exactly — the band only widens when a new extreme sample arrives.

The dashed line is the round average, and the shaded band at the bottom is the theoretical fiber-optic floor (161.6 ms) for this route.

Full 50-sample dataset

Seq	Offset (ms)	RTT (ms)
1	0	287.84
2	100	290.79
3	200	280.16
4	300	282.35
5	400	275.74
6	500	274.06
7	600	275.74
8	700	278.87
9	800	274.76
10	900	279.33
11	1000	278.23
12	1100	281.11
13	1200	277.87
14	1300	277.69
15	1400	280.49
16	1500	286.13
17	1600	285.85
18	1700	277.41
19	1800	296.53
20	1900	289.00
21	2000	278.88
22	2100	274.74
23	2200	282.54
24	2300	279.57
25	2400	281.26
26	2500	281.87
27	2600	275.57
28	2700	282.97
29	2800	275.93
30	2900	273.42
31	3000	279.17
32	3100	274.76
33	3200	300.55
34	3300	296.94
35	3400	299.77
36	3500	282.54
37	3600	277.95
38	3700	274.08
39	3800	281.53
40	3900	275.65
41	4000	277.61
42	4100	282.97
43	4200	278.27
44	4300	279.54
45	4400	281.46
46	4500	294.31
47	4600	292.19
48	4700	280.45
49	4800	289.50
50	4900	289.06

Download This Route's Data

This route's measurement round is published as open data (CC BY 4.0) in CSV, JSON, and YAML. See About This Measurement for citation guidance.

Download this dataset

Per-route ICMP ping series, released under CC BY 4.0. Uncompressed plain text — no decompression step needed.

CSV JSON YAML Full dataset

Theoretical Fiber Latency

The public physical reference uses the GeoNames city centres for Seattle (47.60621, -122.33207) and Johannesburg (-26.20227, 28.04363). It does not disclose either facility address.

Physical Reference	Value
WGS-84 geodesic distance	16,502.7 km
Vacuum RTT floor	110.09 ms
Standard fiber RTT floor ( $n_g=1.4679$ )	161.61 ms
Low-latency fiber material floor	160.96 ms
Engineering floor (5% path allowance)	169.71 ms
Research 1.33× mapped-fiber reference	214.94 ms
Estimated unamplified path loss	3465.6 dB
Transparent optical spans / inline amplifiers	217 / 216
Published RTT inflation over fiber floor	1.75×

Attenuation is used to estimate the number of 80 km optical spans; it does not directly slow light. See the full theoretical fiber latency, GeoNames, attenuation, and amplifier methodology.

Stability & Trend

The current measurement round (2026-08-16T04:07:28Z) collected 50 ICMP echo samples on this route. Distribution statistics from that round:

Round Statistic	Value
Minimum RTT	273.42 ms
Average RTT	282.1 ms
Maximum RTT	300.55 ms
Standard deviation	6.9 ms
Stdev / average	2.4%

RTT trend

Estimated route stability across the selected time window.

Average: 282.6 ms
Minimum: 280.0 ms
Maximum: 284.5 ms
Average loss: 0.02%

Route Context

Departure PoP: Seattle (SEA)
Destination PoP: Johannesburg (JNB)
Region overview: North America → Africa
Full global matrix: Backbone Latency Matrix
Physical methodology: Theoretical Fiber Latency

Reverse direction

Johannesburg to Seattle latency and RTT — 281.2 ms

Fastest routes departing Seattle (SEA)

Seattle to Los Angeles latency and RTT — 25.9 ms
Seattle to New York latency and RTT — 59.5 ms
Seattle to Ashburn latency and RTT — 61.5 ms
Seattle to Miami latency and RTT — 81.7 ms
Seattle to Tokyo latency and RTT — 85 ms

Fastest routes arriving at Johannesburg (JNB)

Amsterdam to Johannesburg latency and RTT — 171.9 ms
Berlin to Johannesburg latency and RTT — 172.1 ms
London to Johannesburg latency and RTT — 179.6 ms
Paris to Johannesburg latency and RTT — 180.9 ms
Frankfurt to Johannesburg latency and RTT — 188.4 ms

Same corridor (North America → Africa)

New York to Johannesburg latency and RTT — 221.5 ms
Ashburn to Johannesburg latency and RTT — 228.3 ms
Miami to Johannesburg latency and RTT — 259.8 ms

About This Measurement

Published RTT reflects best-case backbone path behavior measured with ICMP echo probes between PoPs. End-user latency also depends on local access networks, congestion, routing policy, and traffic engineering. None of these values is an SLA.

The measurement round behind this page is published as open data under CC BY 4.0 in the Hats Network latency dataset. Per-pair files are available at /opendata/latency/latest/pairs/sea-jnb.pings.{csv,json,yaml}. When citing, include the route, the measurement round timestamp, and the dataset version — for example: "Hats Network latency dataset, Seattle → Johannesburg round 2026-08-16T04:07:28Z, CC BY 4.0".

Data auto-generated on August 16, 2026. Explore the full interactive latency matrix or browse more city-pair routes.

Seattle, USA → Johannesburg, South Africa RTT