Warwickshire 112 for 4 (Davies 58) trail Worcestershire 307 (D’Oliveira 76, Waite 53) by 195 runs
The 30-year-old began his innings needing a further 34 and turned Logan van Beek square of the wicket for a boundary to reach the milestone during the morning session.
Surrey batter Rory Burns started the day as Davies’ nearest challenger but he was dismissed for 21 against Somerset with his total on 974.
It was the second time Davies had completed 1,000 runs in a campaign after, in 2017, becoming the first Lancashire wicket-keeper to achieve the feat.
He moved to Warwickshire for the 2022 season and the first two years at Edgbaston produced first class returns of 649 at 28.21 and 437 at 25.70.
This summer he has struck four centuries and averages 56.88.
He eventually fell to Ethan Brookes who delivered an impressive nine-over spell which yielded two wickets before bad light and rain ended play for the day at 2.15pm after 37 overs were possible.
Those spectators who waited until the play was officially called off were entertained via the club PA to a series of weather anthems including ‘Raindrops Keep Falling On My Head’ and ‘It’s Raining Men.’
Warwickshire needed only four overs to polish off the Worcestershire first innings but not before the home side had secured a second batting point.
Jack Home, who was making his Championship debut, pulled Chris Rushworth for successive boundaries to bring up the 300.
But then Rushworth struck twice in the space of three balls.
He ended a stand of 65 between Tom Taylor and Home by trapping the latter lbw for 29 and then knocked out the off stump of on loan Surrey spinner Amar Virdi.
It left Taylor unbeaten on 36 from 49 balls.
Taylor then took the new ball but only five balls were possible before bad light stopped play with Warwickshire 6-0.
When play resumed after a short delay, Taylor made the first breakthrough when Rob Yates tried to work the ball on the leg side and was caught off a leading edge at mid on by Virdi.
Taylor bowled an excellent opening spell and constantly beat the bat.
Davies went to his four-figure milestone in spectacular fashion against Logan van Beek during his first over.
He twice hit the New Zealander for sixes backward of square and then a square drive to the boundary took him past 1,000 in an over costing 16 runs.
Davies completed a 59-ball half-century with three sixes and six fours as Warwickshire reached 76 for 1 off 20 overs by lunch.
But former Warwickshire all-rounder Ethan Brookes struck with the first delivery after the resumption when Will Rhodes aimed to work to leg and inside edged through to keeper Gareth Roderick moving away to his right.
There was more joy for Brookes with the prized scalp of Davies (58) who went for a drive but took his one hand off the bat and inside-edged onto his stumps at 91 for 3.
Van Beek switched ends and claimed his first scalp when Sam Hain (11) tried to turn a delivery on the on-side and was bowled shortly before the players left the field for the final time.
Source: ESPN Crickinfo