Type 1 diabetes doesn't take holidays, but it does have seasons. Children are diagnosed more often in winter, A1C drifts up in the cold months, and parents' questions follow the school and camp calendar. We combined published research with three years of US search data to map the year — and what to do in each month.
January
peak month for new type 1 diagnoses in US children; June is the lowest
0.44–0.67
percentage-point A1C gap between winter and late summer in one study of 589 schoolchildren
+65%
diabetes camp searches in June, versus their yearly average
What the Research Shows
Diagnoses peak in winter
The US SEARCH for Diabetes in Youth study, which tracked new cases at five centers from 2002 to 2018, found a statistically significant yearly pattern in type 1 diabetes diagnoses: the most children were diagnosed in January and the fewest in June. The same study found type 1 incidence in US youth rising by about 2% a year.
The pattern isn't unique to the US. A WHO-backed analysis of more than 31,000 children in 53 countries found a seasonal pattern in 42 centers, most of which peaked in winter and dipped in summer — though not every center showed it, and the cause is still unknown. Proposed explanations include seasonal viral infections and changes in activity and routine.
A1C runs higher in winter
In a three-year study of 677 children with type 1 diabetes in Poland, A1C in schoolchildren was lowest in August and September and highest in November, December and February. The winter–summer gap was 0.44 to 0.67 percentage points, and it tracked the weather: warmer, sunnier months went with lower A1C. Preschoolers didn't show the pattern. The study was observational, so it shows a link, not a cause — but it's a useful reason not to over-read one winter A1C result.
What Parents Search, Month by Month
Average US search volume in each calendar month from October 2023 to September 2026, as an index where 100 is the query's own yearly average.
Search
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
diabetes camp
89
103
110
120
121
165
134
78
65
75
70
70
diabetes 504 plan
93
101
99
88
94
47
63
160
163
133
102
56
ketotic hypoglycemia
103
124
102
108
99
100
100
134
92
63
85
90
type 1 diabetes symptoms
97
107
105
108
94
90
96
94
98
103
116
93
signs of diabetes in kids
107
104
96
98
96
108
106
103
107
93
93
90
type 1 diabetes snacks for school
118
152
153
113
95
70
83
119
67
83
71
76
below average100 = yearly averageabove average
The cycles repeat year after year. Below, three searches are each indexed to their own three-year average so they can share one scale: camp searches rise every spring and peak in June, 504 plan searches jump every August and September, and general type 1 symptom searches peak every November.
Research findings come from the published studies listed below; we report their results as published and did not re-analyze their data. Search data is Ahrefs' estimated monthly US search volume, October 2023 to September 2026 (pulled October 12, 2026). Seasonal indexes average each calendar month across three years and divide by the query's overall monthly average. Small queries (504 plan and school snacks, roughly 30–150 searches a month) are noisy — read their pattern, not individual values. The full search dataset and methods are in our parent search data report.
Limitations: search volume measures interest, not illness. Seasonal research comes from specific populations (US, Poland, and an international registry) and may not match every region, especially in the Southern Hemisphere, where the seasons are reversed.
Moltchanova EV, Schreier N, Lammi N, Karvonen M. Seasonal variation of diagnosis of Type 1 diabetes mellitus in children worldwide. Diabetic Medicine, 2009;26:673–678.