The fans packed in regardless, filling the grandstands with more than 400,000 expected over a sell-out three days at Silverstone compared to last year's attendance of 356,000.
That would make it the biggest three-day attendance at a sporting event in Britain.
The session was red-flagged with a minute to spare after Canadian Lance Stroll beached his Aston Martin in the gravel run-off at Copse.
Verstappen leads Mexican team mate Sergio Perez by 46 points after nine races.
Hamilton has won his home race a record eight times and Mercedes have introduced upgrades for Silverstone, hoping to provide him with a more competitive car after bouncing problems this season.