Does Clean Harbors (CLH) stock go up or down depending on the month?
Clean Harbors month by month, year by year
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | +10.8% | +12.8% | -2.2% | +9.1% | -10.1% | +6.3% | +4.7% | |||||
| 2025 | +1.2% | -8.3% | -7.7% | +8.5% | +6.0% | +1.9% | +2.0% | +2.7% | -4.1% | -9.3% | +8.1% | +3.0% |
| 2024 | -3.8% | +8.4% | +10.5% | -5.9% | +14.3% | +4.4% | +5.6% | +3.0% | -1.7% | -4.3% | +12.5% | -11.5% |
| 2023 | +14.2% | +1.4% | +7.9% | +1.8% | -3.3% | +17.1% | +1.1% | +1.9% | -1.2% | -8.2% | +5.2% | +7.9% |
| 2022 | -7.2% | +3.1% | +17.0% | -6.0% | -11.0% | -6.1% | +11.3% | +20.3% | -6.3% | +11.3% | -2.0% | -4.9% |
| 2021 | +1.8% | +9.9% | -1.3% | +5.8% | +4.7% | +0.0% | +2.0% | +8.0% | +1.2% | +8.3% | -9.9% | -1.6% |
| 2020 | -4.1% | -15.4% | -26.2% | +4.1% | +11.2% | +1.0% | -0.6% | +2.5% | -8.3% | -5.5% | +36.6% | +5.2% |
| 2019 | +20.0% | +14.8% | +5.2% | +6.2% | -15.6% | +10.9% | +9.4% | -5.5% | +5.0% | +6.8% | +0.2% | +3.8% |
| 2018 | +2.1% | -9.8% | -2.2% | -6.2% | +15.7% | +4.8% | +2.5% | +20.5% | +4.4% | -4.9% | -5.2% | -23.5% |
| 2017 | -0.3% | +4.4% | -4.0% | +4.5% | +0.5% | -4.4% | +1.7% | -4.8% | +4.8% | -5.6% | +0.7% | +0.6% |
| 2016 | +6.4% | -3.9% | +15.8% | +0.1% | +4.2% | +1.2% | -1.3% | -7.0% | +0.4% | -1.4% | +11.7% | +5.3% |
| 2015 | -1.5% | +17.7% | +2.0% | -2.7% | +2.0% | -4.6% | -7.9% | -0.8% | -10.5% | +5.7% | -6.9% | -3.8% |
| 2014 | -6.5% | -15.7% | +15.9% | +9.5% | +1.8% | +5.1% | -10.3% | +5.0% | -10.9% | -8.0% | -5.8% | +2.8% |
| 2013 | -7.4% | +12.8% | -1.9% | +0.4% | -11.7% | +11.7% | +0.7% | +3.2% | +5.3% | -14.5% | +13.6% | |
| Average | +2.6% | +0.9% | +3.1% | +1.9% | +1.5% | +1.9% | +2.3% | +3.6% | -1.9% | -0.7% | +2.4% | -0.2% |
| % of years up | 54% | 57% | 57% | 64% | 71% | 71% | 71% | 69% | 46% | 38% | 54% | 62% |
| Years observed | 13 | 14 | 14 | 14 | 14 | 14 | 14 | 13 | 13 | 13 | 13 | 13 |
Clean Harbors month by month: the summary
Over 2013-2026, here's what Clean Harbors (CLH) stock did each month, on average: January +2.6% (up 54% of 13 years), February +0.9% (up 57% of 14 years), March +3.1% (up 57% of 14 years), April +1.9% (up 64% of 14 years), May +1.5% (up 71% of 14 years), June +1.9% (up 71% of 14 years), July +2.3% (up 71% of 14 years), August +3.6% (up 69% of 13 years), September -1.9% (up 46% of 13 years), October -0.7% (up 38% of 13 years), November +2.4% (up 54% of 13 years), December -0.2% (up 62% of 13 years). In other words, CLH historically rose in January, February, March, April, May, June, July, August, November, and fell in September, October, December.
Does Clean Harbors really go up in August?
Over 2013-2026, August is Clean Harbors's strongest month: +3.6% on average, positive in 9 of 13 years. At the other end, September shows -1.9%. But a monthly gap is often built on one or two extreme years — the table above shows it: look at the spread, not just the average. Seasonality only means something when it has a cause (selling season, earnings calendar, year-end tax effects); with no identified cause, it's probably noise.
Frequently asked questions
Does Clean Harbors stock go up or down in May?
Over 14 years, CLH rose +1.5% on average in May, finishing the month up 10 times out of 14 (71%). Median: +1.9%. It's one of its most consistent months. ⚠️ 14 years of data is not a prediction.
Does Clean Harbors stock go up or down in March?
Over 14 years, CLH rose +3.1% on average in March, finishing the month up 8 times out of 14 (57%). Median: +3.6%. Results are split year to year — there's no clear pattern. ⚠️ 14 years of data is not a prediction.
Does Clean Harbors stock go up or down in January?
Over 13 years, CLH rose +2.6% on average in January, finishing the month up 7 times out of 13 (54%). Median: +1.2%. Results are split year to year — there's no clear pattern. ⚠️ 13 years of data is not a prediction.
Does Clean Harbors stock go up or down in November?
Over 13 years, CLH rose +2.4% on average in November, finishing the month up 7 times out of 13 (54%). Median: +0.2%. Results are split year to year — there's no clear pattern. ⚠️ 13 years of data is not a prediction.
Does Clean Harbors stock go up or down in July?
Over 14 years, CLH rose +2.3% on average in July, finishing the month up 10 times out of 14 (71%). Median: +2.0%. It's one of its most consistent months. ⚠️ 14 years of data is not a prediction.
Does Clean Harbors stock go up or down in April?
Over 14 years, CLH rose +1.9% on average in April, finishing the month up 9 times out of 14 (64%). Median: +2.9%. Results are split year to year — there's no clear pattern. ⚠️ 14 years of data is not a prediction.
What is the best month to buy Clean Harbors stock?
Historically, August: over the last 14 years, CLH gained +3.6% on average that month and finished up 69% of the time (13 years observed). September is the weakest month (-1.9%). This is not a prediction: 14 years is a small sample, and the past is under no obligation to repeat.
Why does Clean Harbors stock often rise in August?
August has averaged as its best month over 14 years (+3.6%, up 69% of years). No clearly established recurring seasonal driver explains this month — it's a statistical tendency over 14 years of history, not a prediction.
Is there a best month to invest in the stock market in general?
There's no universal rule: every stock has its own seasonality. For CLH it's August (+3.6% on average over 14 years) — another stock will look completely different. The calendar effects people cite ("sell in May", the year-end rally) are market-wide averages, not laws: on CLH, May is the most consistent month (71% positive years). We also rank all 12 months for the whole market.
Does stock seasonality actually work?
Careful. A month that rose 14 times out of 14 can simply be chance: with 12 months and a dozen years, patterns appear naturally even in random data. Seasonality describes what happened; it doesn't explain why and predicts nothing. Treat it as context, never as a standalone buy signal.
What data is this table based on?
On CLH's real monthly closing prices from 2013 to 2026 (14 years), source Yahoo Finance. Each cell = the price change over that month. Price performance, excluding dividends. Incomplete months and quote gaps are excluded.