The takeaway
Comfort Systems USA Inc shows a pronounced seasonal pattern over 10 years of data — strongest in October (+8.9%) and softest in December (−2.0%).
Right now
In July, the stock has risen 60% of years, averaging +8.4%, about +6.2 pts better than the S&P 500.
The full picture
Comfort Systems USA Inc's most dependable month has been October, higher in 7 of 10 years; December has been its least reliable, up just 50% of the time.
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Month by month
The stock's clearest edge over the S&P 500 lands in October (+7.8 pts); it has trailed the market most in December (−3.0 pts).
“vs S&P” is Comfort Systems USA Inc’s average for a month minus the S&P 500’s average for that same month — isolating Comfort Systems USA Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, October has closed higher 100% of the time versus 70% across the last 10 years — the pattern is strengthening.
Figures are the typical (median) October return and how often it rose — the last 5 years versus the last 10(the heatmap’s default window). This verdict stays anchored to that 10-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
Dependability is the through-line here. October stands out, higher in 7 of 10 Octobers, but it heads a clutch of months that pull the year reliably upward.
Its average (+8.9%) and median (+12.6%) land within a hair of each other — the tell of steady, year-after-year gains rather than one outlier doing the work. That reliability comes with real swings, mind — even October ranges by 11.4% from year to year, so any single year can land far from the average. Crucially, the gain is the stock's own rather than a rising tide's: October has cleared the S&P 500 by +7.8 points above the index. That consistency sets it apart from the field, where the average stock manages October only about 53% of the time.
The strength clusters rather than stands alone — April–November forms a firm stretch that carries much of the year. The weaker half of the year is plainer: December has been the soft spot — the only month to average an outright loss (−2.0%), and the edge isn't year-round — the stock has trailed the S&P 500 in December and March. Its roughest month on record was a −18.0% July in 2019 — a reminder of how hard even a seasonal name can fall.
October has now closed higher 5 years running. If anything it has sharpened recently — the last five Octobers run ahead of the earlier years.
The takeaway is less about when to buy than what to expect: October aside, the stock's months offer little reliable tilt.
Short answers on the stock's best month (October), its worst (December), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2016 its best month (October, +8.9%) has run well ahead of its worst (December, −2.0%) — the heatmap above shows how steady that gap has been year to year.
October has been the strongest, averaging +8.9% and closing higher in 7 of 10 years since 2016.
It's the weakest, averaging −2.0% — historically a soft spot, though it still varies from year to year.
Explore
These names have the strongest July track records on record — a starting point for comparison.
Before you trade