Pacific Standard Time (PST, UTC−8) and Greenwich Mean Time (GMT, UTC+0) sit 8 time zones apart, creating one of the most challenging scheduling gaps in the US-to-Europe corridor. For technology companies headquartered in San Francisco or Seattle that work with UK partners or clients, the PST/GMT gap requires deliberate scheduling strategies rather than ad-hoc calls.

The 8-Hour Gap

PST is UTC−8 and GMT is UTC+0, placing London 8 hours ahead of Los Angeles and San Francisco. When Silicon Valley wakes up at 8 AM PST, London is already at 4 PM GMT, nearing end of day. When San Francisco starts its trading day at 9:30 AM PST, London’s markets are at 5:30 PM GMT and closing.

In summer, both PST and GMT shift (to PDT at UTC−7 and BST at UTC+1), maintaining the 8-hour gap. However, during the approximately 2-week window in mid-March when the US has changed to PDT but the UK has not yet switched to BST, the gap narrows to 7 hours. Similarly, in late October after the UK falls back to GMT before the US falls back to PST, the gap is also 7 hours. These windows are the friendliest for West Coast / UK scheduling.

The Very Narrow Overlap Window

The only practical overlap between PST business hours (9 AM–6 PM PST) and GMT business hours (9 AM–6 PM GMT) is 4–6 PM GMT (8–10 AM PST). This two-hour window asks London to schedule in late afternoon and San Francisco in early morning.

In summer (PDT/BST), the window shifts slightly: 4–6 PM BST is 8–10 AM PDT. The practical outcome is the same. Many West Coast companies set their UK calls between 8 and 9 AM local time as a standing policy, accepting that this is the price of transatlantic collaboration.

Quick Conversion Reference

To convert PST to GMT, add 8 hours. To convert GMT to PST, subtract 8 hours.

Strategies for West Coast / UK Teams

Given the narrow overlap, West Coast companies with UK teams develop one of a few strategies. Some rotate the inconvenient slot, alternating between early Pacific mornings one week and late UK evenings the next. Others designate the 8–9 AM PST window as the permanent “UK hour” for synchronous collaboration and keep the rest of the day asynchronous.

Asynchronous-first communication is particularly well-suited to PST/GMT teams. London records video updates, Slack messages, or loom walkthroughs at end of day, and San Francisco picks them up at the start of their morning. The day-end UK message becomes the day-start West Coast context. This can feel like a near-synchronous workflow despite the 8-hour gap.