晚上国际带宽很小是 ISP 的原因吗？

家用联通10Mb光纤，每天都会有一些时段到美国的带宽低得可怜，只有几百Kbps。一直认为是ISP的原因，不过刚才在VPS上测试了一下，貌似这一时段美国到整个亚太地区的带宽都不高唉~这是为什么呢？

VPS：搬瓦工，洛杉矶机房
测试时间：今天22：00～22：10
测试工具：speedtest-cli

加拿大：
[root@default ~]# speedtest-cli --server=4240 --share
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from IT7 Networks (104.224.XXX.XX)...
Hosted by Shaw Communications (Victoria, BC) [1654.04 km]: 42.105 ms
Testing download speed........................................
Download: 186.62 Mbits/s
Testing upload speed..................................................
Upload: 64.89 Mbits/s
Share results: http://www.speedtest.net/result/4071677925.png

新加坡：
[root@default ~]# speedtest-cli --server=3914 --share
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from IT7 Networks (104.224.XXX.XX)...
Hosted by SingTel (Singapore) [14126.60 km]: 272.439 ms
Testing download speed........................................
Download: 54.97 Mbits/s
Testing upload speed..................................................
Upload: 12.69 Mbits/s
Share results: http://www.speedtest.net/result/4071688390.png


日本：
[root@default ~]# speedtest-cli --server=5618 --share
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from IT7 Networks (104.224.XXX.XX)...
Hosted by (Suzuka) [9097.56 km]: 528.332 ms
Testing download speed........................................
Download: 66.51 Mbits/s
Testing upload speed..................................................
Upload: 3.73 Mbits/s
Share results: http://www.speedtest.net/result/4071679593.png

中国：
[root@default ~]# speedtest-cli --server=5017 --share
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from IT7 Networks (104.224.XXX.XX)...
Hosted by China Unicom,Liaoning Branch (Shenyang) [9474.05 km]: 219.469 ms
Testing download speed........................................
Download: 29.55 Mbits/s
Testing upload speed..................................................
Upload: 2.23 Mbits/s
Share results: http://www.speedtest.net/result/4071659370.png