People who are homeless say being stuck outside in extreme heat is "horrendous" and "makes me sick".
Bristol Street Outreach Team, operated by charity St Mungo's, has been carrying out additional shifts and giving out water, advice and sun protection.
It has also opened up an additional day centre for those who need shelter.
Michael, who sleeps rough in the city, said even sitting in the shade was "tiring and sweaty and uncomfortable".
"It makes me sick," he added.
Temperatures are forecast to hit 37°C (99°F) in some parts of the country over the next couple of days.
James Bennett, an outreach worker for the St Mungo's Rough Sleeper Service – which is funded by Bristol City Council, said: "A lot of the people who are sleeping rough are quite vulnerable so it can be quite dangerous in the heat."
Zoe, who used to be homeless, said she had sunstroke three times during her time living in a tent.
"I was in bed for five days once, sick in hospital with it," she added.
"It's horrendous. Being in a tent from 8pm to 7am in this heat is not good," added Mel, who has slept rough for four years.
St Mungo's said it encouraged those who pass by homeless people to hand out bottles of water, or in an emergency call 999 or contact Streetlink, which provides support for rough sleepers.
"You can put in a description and a location of a person and the outreach team get that referral, and then will go out and see that person," added outreach worker Hannah Mummery.
She said teams were working all weekend to support homeless people through the heat.
Many councils have activated a Severe Weather Emergency Protocol (SWEP), which is usually used to help rough sleepers during extreme cold weather.
In Bristol, SWEP has been activated twice already this year for hot conditions and is currently in place from Thursday to Sunday.
The UK government has declared a drought across parts of the South West, parts of southern and central England, and the east of England.
Follow BBC West on Facebook, Twitter and Instagram. Send your story ideas to: bristol@bbc.co.uk
'Safe spaces' offered for people to escape heat
Emergency plan to protect homeless people
Rough sleepers warned of 'killer weather'
More funds needed to tackle homelessness – council
Bristol Severe Weather Emergency Protocol
Streetlink
St Mungo's
M5 crash live: Miles of traffic after incident near Bristol
Seven vehicles damaged by fire in Bristol as police investigate arson
Pictures show police deal with man on rooftops in Weston Charlie Williams
Hospital bosses declare critical internal incident as ambulances diverted to Bristol Royal Infirmary
Photos of Victorian Bristol and how the city looks now – The Centre, Park Street, Temple Meads and more
See Monster See Monster viewing platform to open next week Charlie Williams
Rushdie's 'defiant sense of humour' remains – son
Dozens dead in Egypt church fire
'We are waiting for rain, for winter, for God'
Why S Korea just pardoned the Samsung 'prince'
The mystery deaths of two Saudi sisters in Sydney
The librarian who defied the Taliban
Why Hong Kong is seeking solace in local pop
New Netflix dark comedy turns tables on wife beaters
Why Sir Ganga Ram's legacy lives on in India and Pakistan
The humiliating story that made me a break-up coach
Evacuated twice in a summer as France's fires burn
The Partition baggage for young Indians and Pakistanis. VideoThe Partition baggage for young Indians and Pakistanis
The best public pools around the world
Why open relationships are on the rise
The ejector seats that fire through the floor
© 2022 BBC. The BBC is not responsible for the content of external sites. Read about our approach to external linking.

source