Toronto is now in its fourth day of back-to-back heat warnings, with humidex values pushing into the low 40s C during a blistering wave of weather that is serving to herald the official start to summer.

As citizens try their best to keep cool, the city is very much getting beaten by the heat in some ways, with some things inevitably disrupted by the sky-high temps.

Metrolinx had to issue an advisory on Tuesday afternoon to let passengers know that certain GO Train routes were running at lower speeds, and others completely cancelled due to the temperature's effect on the rails, which "have the potential to soften and expand."

Hi there Miriam, the 16:53 LE westbound was cancelled due to extreme heat conditions. We are inspecting the track to ensure the safety of your travel. We apologize for any inconvenience caused. ^KT

— Lakeshore East Train (@GOtransitLE) June 18, 2024

Given the heat wave, officials at Woodbine Racetrack also decided to make some changes, altering certain race schedules in the interest of the health and safety of the horses.

All outdoor programs are cancelled today (June 20th) due to the extreme heat. We're sorry for the inconvenience!

— BridgeWay Family Centre (@bridgewaycentre) June 20, 2024

A number of outdoor events in not just Toronto, but all over Southern Ontario have also been postponed, including recreational sports games and practices, social events, special ceremonies and City-led initiatives and public library programming.

And, TDSB teachers are taking special measures to try and lower classroom temperatures, like turning off lights, closing blinds, opening windows and limiting physical activity.

Many online say they are also amending their own personal plans for the week in light of the multi-day scorcher.

In response to the conditions, a handful of outdoor pools are running on extended hours as part of T.O.'s Heat Relief Strategy, which includes street outreach and specially designated cool spaces for public drop-in.

Toronto Public Health is reminding residents today to avoid strenuous outdoor activity, drink lots of water, seek shade, check in on vulnerable loved ones and, of course, don't leave any living thing in a parked car amid this dangerous system.

It’s day 3 of the #HeatWarning.🥵
Stay inside if you can & keep blinds closed.
Check on family, friends & neighbours.
If you know someone without A/C, invite them into your place if you have a cool space.

If you need a place to cool down, find a space: https://t.co/XnGwm1s3Uf pic.twitter.com/peicn4dg5G

— City of Toronto (@cityoftoronto) June 19, 2024

According to the latest alert from Environment Canada, Thursday's daytime highs are expected to be 30-34 C, but will feel like 40-44 C, with "little relief through the overnight," with humidex values of 26-30 C after dark.

"Hot and humid air can also bring deteriorating air quality and can result in the Air Quality Health Index approaching the high risk category," the agency continues.

"Watch for the effects of heat illness: swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions."