Ontario Summer Heat: Sick Notes for Heat-Related Illness

Ontario summers bring extreme heat events that can cause heat exhaustion and heat stroke. Learn when you need a sick note and your rights as a worker.

Summer Heat and Worker Health in Ontario


Ontario summers regularly bring extreme heat events, with humidex values exceeding 40°C in southern Ontario.

When Heat Illness Warrants a Sick Note


  • Heat exhaustion requiring recovery time

  • Heat stroke (medical emergency — seek immediate care)

  • Dehydration affecting work performance

  • Pre-existing conditions exacerbated by heat

  • Medication interactions with heat exposure


Outdoor Worker Protections


Ontario's Occupational Health and Safety Act requires employers to protect workers from heat stress. If protections are inadequate, you may have grounds for a WSIB claim.

Vulnerable Workers


  • Construction workers

  • Landscapers and agricultural workers

  • Warehouse workers without AC

  • Delivery drivers

  • Workers on medication affecting heat tolerance


Getting Documentation


MedLetter provides same day sick notes from CPSO-registered physicians for heat-related illness.

Ontario Employment Standards: Your Rights

Under Ontario's Employment Standards Act, 2000 (ESA), employees are entitled to 3 unpaid sick days per year (some employers offer paid days). Important provisions:

  • Employers cannot require a doctor's note for ESA-protected sick days as of January 2024 (Working for Workers Act amendments)

  • The Ontario Human Rights Code requires employers to accommodate medical conditions to the point of undue hardship

  • Federally regulated employees in Ontario get 10 paid sick days under the Canada Labour Code

  • Many Ontario employers still request notes as a matter of company policy (distinct from legal requirement)


Statistics: Healthcare Access in Ontario

According to Ontario Health and Statistics Canada (2025-2026):

  • 2.3 million Ontarians lack a regular family doctor or nurse practitioner

  • Average emergency room wait time in Ontario: over 4 hours for non-urgent cases

  • Walk-in clinic wait times in the GTA: 1.5-3 hours on average

  • Ontario has the lowest physician-to-population ratio of any large province


Practical Steps for Ontario Employees

1. Know the ESA - Your employer cannot penalize you for taking your 3 statutory sick days
2. Check your employment contract - Many Ontario employers offer 5-10 paid sick days beyond the ESA minimum
3. Unionized workers - OPSEU, CUPE, and Unifor contracts typically provide 12-18 paid sick days annually
4. Document everything - Keep a record of when you called in and who you spoke to
5. Accommodation requests - If you have a chronic condition, consider requesting formal workplace accommodation under the OHRC

When a Sick Note May Not Be Required

Under Ontario law, a sick note is generally not required for:

  • Your 3 annual ESA sick days (Working for Workers Act, 2024)

  • Family responsibility leave (up to 3 days)

  • Bereavement leave (up to 2 days)

  • Domestic or sexual violence leave

Understanding Mental Health Documentation

Mental health conditions are legitimate medical reasons for workplace absence. The Canadian Mental Health Association reports:

  • 1 in 5 Canadians experiences a mental health condition in any given year

  • Mental health conditions account for approximately 30% of short-term disability claims

  • Anxiety and depression are the most common reasons for mental health-related work absences

  • Early intervention and appropriate time off can prevent longer-term disability


What a Mental Health Sick Note Covers

A physician can document:

  • Inability to perform job duties due to mental health symptoms

  • Recommended duration of absence

  • Any workplace modifications needed upon return

  • Referral recommendations (without disclosing specific diagnosis to employer)


Your employer is not entitled to know your specific diagnosis. The note only needs to confirm you have a medical condition that prevents you from working.

Related: [Sick Note Ontario — Complete City Guide](/sick-note-ontario) | [Ontario Sick Note Cost 2026](/blog/ontario-sick-note-cost-2026)

Frequently Asked Questions

Can I get a sick note online in Ontario?
Yes. CPSO-licensed physicians can assess patients through virtual consultations and issue legally valid sick notes accepted by all Ontario employers.

How much does an online sick note cost in Ontario?
MedLetter charges a flat $49 for a sick note with same-day delivery. This includes the physician assessment and official documentation.

Will my Ontario employer accept an online sick note?
Yes. The College of Physicians and Surgeons of Ontario recognizes virtual care. Online sick notes are legally equivalent to in-person notes.

How long does it take to get a sick note from MedLetter?
Most sick notes are delivered within 2-6 hours of submission. Same-day delivery is standard.