Why do my symptoms always get worse in the same season every year?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group

Published: July 28, 2025Updated: July 28, 2025

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Key Takeaways

Season-linked health problems usually arise from three overlapping forces: environmental exposures that spike at predictable times (pollen, mold, cold air), changes in your immune and hormone balance driven by daylight and temperature shifts, and behavior patterns such as holiday diets or summer travel. Tracking these factors allows you and your clinician to predict flares, order timely tests, and start preventive steps weeks before symptoms hit.

Why does my health dip around the same months every year?

Seasonal symptoms typically trace back to predictable external or internal changes. Understanding the most common drivers can reveal why you cough every April or feel fatigued each November.

Pollen counts peak in spring and fallTree pollen usually surges March-May, grass May-July, and ragweed August-October. A 2023 US study found emergency visits for asthma climb 18 % on days when ragweed tops 50 grains/m³. "Many patients think their cold is ‘just bad luck’ when the culprit is actually airborne pollen," notes the team at Eureka Health.
Respiratory viruses thrive in colder, drier airRhinovirus and influenza survive longer at 40 % relative humidity than at 60 %. That means October through February brings a higher viral load indoors.
Vitamin D drops in late autumnLess sun equals lower serum 25-OH vitamin D; levels below 20 ng/mL are linked to higher rates of eczema flares and joint pain. Sina Hartung, MMSC-BMI, explains, "We routinely see patients’ lab values fall by up to 30 % after daylight saving time ends."
Behavior shifts create metabolic stressHoliday meals add an average of 0.5-1 kg; combined with alcohol and sleep loss, this can worsen heartburn, migraines, and mood disorders.
Thousands of immune-related genes switch on in winterA Nature Communications analysis of 22,822 human genes found that 5,136 (about 23 %) change expression with the seasons; winter months showed a distinctly pro-inflammatory profile with elevated IL-6 receptor and C-reactive protein levels. (Nature)
Seasonal Affective Disorder impacts roughly 5 % of adults annuallyMayo Clinic reports that reduced daylight in late fall and winter disrupts circadian rhythms, causing depression-like symptoms in about one-twentieth of the U.S. adult population each year. (Mayo)

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When should seasonal symptoms be treated as an emergency?

Most seasonal issues are bothersome, not dangerous, but certain signs mean you should seek care fast.

Wheezing that limits a full sentenceAny episode requiring rescue inhaler more than twice in an hour, or peak flow under 50 % of personal best, warrants urgent care. "Asthma deaths still cluster in the September ‘back-to-school’ spike, so do not delay," warns the team at Eureka Health.
Hives with lip or tongue swellingAnaphylaxis can follow outdoor exposures like bee stings or fresh produce high in pollen proteins; call emergency services immediately.
Fever over 39 °C with stiff neck in flu seasonCould signal bacterial meningitis; incidence rises in winter when people gather indoors.
Sudden vision changes during spring allergy seasonSevere allergic conjunctivitis can raise intraocular pressure and threaten the optic nerve.
Chest pain or bluish lips during viral outbreaksBeaumont warns that any episode of cold, flu, RSV, or COVID-19 accompanied by chest pain or bluish lips/face is a red-flag for low oxygen and requires immediate ER care. (Beaumont)
Vomiting that prevents hydrationSevere or persistent vomiting that stops you from keeping fluids down can rapidly lead to dangerous dehydration, and Wesley Healthcare recommends going straight to the ER when this occurs. (WesleyHC)

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Which environmental triggers spike at specific times of year?

Pinpointing the irritant or pathogen that surges in your region lets you plan avoidance and treatment.

Mold spores explode after heavy summer rainsCounts can exceed 50 000 spores/m³ within 24 h of a thunderstorm—strong enough to trigger “thunderstorm asthma.”
Dust-mite load climbs in humid late summerBedroom humidity above 50 % lets mite populations double in two weeks, worsening eczema and sinusitis.
Cold-air bronchospasm peaks below 10 °CAirway nerves cool, causing up to 25 % drop in FEV1 in exercise-induced asthma.
UV index rises sharply in late springPhotosensitive conditions like lupus rash flare when UV index surpasses 6; monitoring local weather apps helps adjust sun protection.
Fire-season smoke elevates PM2.5Western US wildfires typically peak July-September, increasing emergency cardiac visits by 7 % per 10 µg/m³ rise in PM2.5. Sina Hartung, MMSC-BMI, adds, "Even patients without asthma report chest tightness during smoky weeks."
Ragweed pollen spikes in early- to mid-SeptemberIn the East and Midwest, ragweed counts climb sharply at the end of summer, with the highest daily levels occurring in the first half of September—so starting antihistamines a couple of weeks beforehand can blunt symptoms. (ACAAI)
Climate change is extending and intensifying pollen seasonsResearchers found North American pollen seasons grew 20 days longer and pollen concentrations rose 21 % between 1990 and 2018, meaning allergy flares now persist well beyond traditional spring windows. (Sierra)

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What daily habits can reduce seasonal flare-ups?

Small, timed adjustments often prevent or blunt symptom waves.

Start nasal saline two weeks before pollen seasonRinsing twice daily cuts airborne allergen load by 60 % in the nasal cavity.
Use HEPA filtration overnightPortable units drop indoor PM2.5 by 50-70 %; studies show a 30 % reduction in winter cough days. "Patients are surprised how quickly nocturnal symptoms settle once air quality is controlled," says the team at Eureka Health.
Schedule outdoor exercise at low-count hoursPollen counts are lowest 4-8 a.m. after rain; running then reduces exposure time.
Boost vitamin D from September to MarchTalk to your clinician about testing; maintaining 30-50 ng/mL supports immune balance.
Shower and change clothes after every high-pollen outingRinsing pollen off skin and hair and swapping garments keeps allergens from settling on bedding and carpets, a simple step highlighted by fall-allergy guidelines. (HHC)
Protect sleep to dampen the inflammatory surge that fuels symptomsThe MGI Clinic notes that short or disrupted sleep heightens inflammatory pathways and can worsen congestion, so aim for a steady 7–8-hour schedule during peak seasons. (MGI)

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Which tests, vaccines, or medicines might your clinician discuss?

Evidence-based interventions can be timed to the season for best effect.

Serum IgE and specific allergy panels in late winterTesting before spring identifies tree pollen sensitivities so immunotherapy can start by January.
Pre-seasonal influenza vaccinationA 2022 CDC analysis showed 52 % lower hospitalization when shots were given by mid-October rather than November.
Spirometry in August for school-age asthmaticsBaseline FEV1 under 80 % predicts September exacerbations; adjusting inhaled steroid dose in advance reduces ER visits by 37 %. "Lab data lets us be proactive instead of reactive," notes Sina Hartung, MMSC-BMI.
Allergen-specific immunotherapy over 3-5 yearsCan cut long-term symptom scores by 65 %; discuss risks and schedule with an allergist.
Short preventive courses of intranasal corticosteroidStarting 7–14 days before expected pollen rise halves peak-season nasal congestion.
Updated COVID-19 booster in early fallCDC advises getting the 2024-25 COVID-19 vaccine before viral activity rises; the virus caused over 916,300 hospitalizations and 75,500 deaths in 2023 alone. (CDC)
One-dose RSV vaccine for adults 60+ before winterNewly authorized RSV vaccines can be offered in late summer or early fall to adults ≥60 years, providing protection when RSV hospitalizations typically spike. (CDC)

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How can Eureka’s AI doctor pinpoint your personal seasonal pattern?

The app analyzes symptom logs against regional weather, pollen, and infection data to surface correlations you may miss.

Automated pattern detection across yearsUpload past clinic notes or diary entries; the AI flags recurring weeks when symptoms spike.
Custom reminders before predicted flaresIf the algorithm sees ragweed rising next week, you receive a push notification to start preventive sprays.
Integrated lab trackerLink your lab portal; the AI highlights drops in vitamin D or lung function that coincide with symptom months.
24/7 chat with clinicians for clarificationThe team at Eureka Health reviews AI findings and can propose next steps within hours.

Getting ongoing, private support through Eureka’s AI doctor app

Continuous guidance matters because seasons return every year. Eureka offers a secure channel to adjust plans without repeated office visits.

Symptom scorecards show clear progressUsers who log at least twice a week report a 41 % drop in peak-season symptom severity.
On-demand prescription reviewThe AI can suggest refills or step-up therapy; a licensed doctor confirms safety before anything is sent to your pharmacy.
High patient satisfactionPeople managing cyclical problems rate Eureka 4.6/5 for ‘feeling heard,’ according to an internal 2024 survey.
Confidential, HIPAA-compliant storageYour seasonal triggers, photos, and lab results stay encrypted and can be deleted at any time. "We built privacy in from day one so patients can share freely," stresses the team at Eureka Health.

Frequently Asked Questions

Can I suddenly develop seasonal allergies as an adult?

Yes. Up to 30 % of new allergy diagnoses occur after age 30, often after moving to a region with unfamiliar pollens.

Do air purifiers help with viral infections too?

HEPA units can reduce airborne virus particles, but hand hygiene and vaccination remain essential.

Is there a best time to check vitamin D?

Late winter (February–March) usually shows your yearly low and guides supplementation plans.

Should I take antihistamines every day in pollen season?

Continuous use is often more effective than taking pills only when miserable, but confirm safety and interactions with your clinician.

How long before a trip should I start malaria prophylaxis?

For most drugs, 1–2 weeks before travel; seasonal timing matters if you live in a region with predictable transmission peaks.

Why do my migraines worsen in spring?

Barometric pressure swings and higher histamine levels in pollen season can both trigger headaches.

Can Eureka’s AI order lab work directly?

Yes. The algorithm suggests labs and a licensed doctor reviews and approves orders if appropriate.

Is it safe to exercise outdoors during wildfire season?

Only when AQI is below 100; otherwise move workouts indoors and use a respirator mask rated N95 or higher.

Does honey really help with pollen allergies?

Evidence is limited; locally sourced honey contains pollen but not always at therapeutic levels.

References

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