Home-Internet download speeds have fallen during the COVID-19 pandemic in dozens of the biggest US cities as millions of Americans stay home due to school and business closures. However, typical download speeds remain high enough to support normal broadband-usage patterns, with the vast majority of cities still above the Federal Communications Commission's 25Mbps standard.

In 88 of the 200 most populous US cities, Internet users "experienced some degree of network degradation over the past week compared to the 10 weeks prior," BroadbandNow said in a report released Wednesday. Of those, 27 cities suffered speed reductions of at least 20 percent.

New York City speeds fell by 24 percent, with median download speeds down to 51.93Mbps—still enough for bandwidth-intensive services like streaming video. While New York City has been hit hard by the spread of the novel coronavirus, the city's broadband experience isn't replicated everywhere. Seattle, where the virus is also rampant, hasn't suffered a drop in download speeds, though Seattle's speeds were already below New York City's. Seattle's most recent median-download speed was 27.1Mbps, while Seattle's median results ranged from 20.8Mbps to 29.1Mbps in the previous 10 weeks.

"Three cities—Austin, Texas; Winston-Salem, North Carolina; and Oxnard, California—have experienced significant degradations, falling out of their ten-week range by more than 40 percent," the report said.

The report compared median download speeds between March 15 and March 21 to the range of median speeds observed each week since January 1. A city's download speeds were only considered to have fallen out of range if the most recent week's median was lower than the lowest measurement from the previous 10 weeks. Check out the report to see the results from all 200 cities.

Despite big speed drops in some cities, BroadbandNow offered a positive takeaway: "Users in most of the cities we analyzed should be experiencing normal network conditions, suggesting that ISPs (and their networks) are holding up to the shifting demand."

BroadbandNow is a company that provides an online tool for checking broadband availability. The company's analysis relied on speed-test data from M-Lab.

DSL and upload speeds may face problems

Since BroadbandNow focused on the 200 biggest cities, the report mainly covers cable and fiber connections. The report said "it remains to be seen if rural communities reliant on legacy technologies such as DSL will continue to enjoy the same relative stability" measured in major cities.

Another limitation in the report is that it only provided download speeds. While fiber-to-the-home telecoms generally offer symmetrical upload and download speeds, DSL and cable networks provide upload speeds that are much slower than downloads. Increased use of video conferencing from more people working at home could cause problems on networks with low upload speeds.

Verizon, which offers home and mobile Internet service, said yesterday that it is "seeing tremendous amounts of usage across our networks as our customers are finding new and important ways of staying connected." For example, Verizon said usage of collaboration tools rose 47 percent in one week. But the ISP said its network has enough capacity to meet the demand.

Netflix and YouTube both started reducing video-streaming quality in Europe last week after facing pressure from a European government official, even though ISPs said their networks were holding up well. Netflix hasn't done the same in the US, but Bloomberg reported that YouTube has since extended its policy worldwide. When I tested this today, YouTube videos streamed in 720 by default, but it was still possible to manually change the quality of individual videos to 1080p or 4K.

Another sign that networks are mostly holding up well came from ThousandEyes, a network-analysis-software vendor. The company said on Monday that it has seen only a slight increase in outages over the past three weeks and some performance degradation. "Despite massive traffic increases—particularly across consumer last-mile networks—we have not seen a significant corresponding spike in Internet outages, which can occur when traffic levels strain network capacity," the company said.