Sainte-Anne-des-Monts
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sainte-Anne-des-Monts clear sky chart from 2005-11-06 to 2026-03-18.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	16% 11% 4 10% 6% 5% 5% 4 5% 6% 27%	131096
	Night	16% 15% 5% 13% 8% 6% 5% 3 4 5% 20%	130600
Transparency	Day	59% 6% 12% 17% 6%	134508
	Night	66% 6% 10% 13% 5%	135263
Seeing	Day	29% 18% 28% 18% 7% 1	17958
	Night	28% 17% 24% 22% 9% 1	25817

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 25% 8% 14% 11% 13% 4 2 3 3 4	4093
	11th to 20th	Day	9% 23% 10% 22% 12% 4 4 3 3 3 7%	4084
	21st to end	Day	2 8% 6% 15% 12% 16% 13% 8% 5% 5% 10%	5122
February	1st to 10th	Day	7% 14% 6% 14% 10% 9% 7% 4 5% 5% 17%	1866
	11th to 20th	Day	10% 17% 6% 14% 7% 6% 6% 6% 4 5% 17%	1843
	21st to end	Day	7% 15% 5% 9% 8% 6% 7% 6% 7% 6% 24%	1618
March	1st to 10th	Day	13% 16% 5% 12% 7% 7% 8% 4 4 6% 18%	4758
	11th to 20th	Day	18% 17% 4 10% 5% 7% 6% 5% 6% 6% 17%	5057
	21st to end	Day	19% 17% 6% 10% 8% 4 3 2 4 5% 21%	5466
April	1st to 10th	Day	16% 15% 5% 11% 6% 4 4 4 5% 5% 25%	2428
	11th to 20th	Day	14% 13% 4 8% 6% 4 5% 4 5% 7% 32%	2572
	21st to end	Day	21% 12% 3 7% 4 4 4 4 5% 5% 32%	2600
May	1st to 10th	Day	22% 10% 3 7% 4 4 4 3 5% 6% 31%	6088
	11th to 20th	Day	22% 9% 3 7% 4 4 4 3 5% 7% 31%	6499
	21st to end	Day	21% 9% 3 6% 4 4 4 3 4 7% 34%	7451
June	1st to 10th	Day	20% 8% 3 7% 5% 5% 4 4 6% 7% 30%	3000
	11th to 20th	Day	19% 7% 2 6% 4 4 4 4 6% 7% 36%	3000
	21st to end	Day	21% 8% 2 7% 4 4 5% 4 6% 8% 31%	3000
July	1st to 10th	Day	17% 7% 2 7% 5% 4 5% 4 6% 7% 35%	6820
	11th to 20th	Day	16% 6% 2 7% 5% 5% 6% 4 6% 9% 35%	6820
	21st to end	Day	12% 6% 2 6% 4 4 4 4 6% 8% 45%	7349
August	1st to 10th	Day	13% 5% 2 6% 4 4 5% 5% 6% 9% 41%	4273
	11th to 20th	Day	15% 6% 3 7% 5% 5% 5% 4 7% 8% 33%	4175
	21st to end	Day	16% 5% 2 5% 4 4 4 4 6% 8% 42%	4675
September	1st to 10th	Day	20% 7% 2 6% 4 3 4 3 5% 7% 38%	2455
	11th to 20th	Day	24% 7% 2 5% 3 3 3 2 4 6% 41%	2205
	21st to end	Day	19% 9% 3 6% 5% 3 5% 3 6% 7% 36%	2200
October	1st to 10th	Day	19% 9% 2 7% 5% 4 5% 4 5% 6% 35%	2019
	11th to 20th	Day	23% 13% 3 7% 5% 4 4 3 5% 6% 26%	2000
	21st to end	Day	24% 15% 4 8% 5% 4 5% 4 4 6% 22%	1991
November	1st to 10th	Day	22% 16% 6% 10% 4 4 4 4 5% 5% 19%	1665
	11th to 20th	Day	21% 19% 8% 12% 5% 4 4 3 4 5% 15%	1680
	21st to end	Day	22% 20% 7% 17% 6% 4 4 3 4 4 9%	1633
December	1st to 10th	Day	11% 21% 13% 23% 8% 5% 4 2 3 4 5%	2350
	11th to 20th	Day	16% 16% 8% 22% 10% 6% 5% 2 2 3 9%	2688
	21st to end	Day	10% 16% 6% 19% 13% 7% 5% 3 4 4 12%	3553
January	1st to 10th	Night	15% 27% 7% 14% 12% 9% 4 2 3 3 4	8831
	11th to 20th	Night	10% 18% 8% 24% 11% 7% 4 2 3 3 8%	8831
	21st to end	Night	3 11% 6% 18% 11% 11% 15% 5% 4 4 10%	9057
February	1st to 10th	Night	8% 15% 6% 12% 12% 9% 6% 4 5% 5% 18%	2753
	11th to 20th	Night	12% 19% 5% 13% 9% 9% 6% 4 5% 5% 14%	2663
	21st to end	Night	9% 16% 6% 11% 9% 7% 5% 4 5% 6% 23%	2186
March	1st to 10th	Night	13% 16% 5% 12% 8% 8% 6% 3 4 5% 20%	5301
	11th to 20th	Night	19% 22% 5% 11% 6% 5% 4 3 4 5% 15%	5057
	21st to end	Night	22% 20% 4 10% 8% 4 3 2 4 5% 18%	5466
April	1st to 10th	Night	20% 15% 4 11% 7% 5% 4 4 4 5% 21%	1970
	11th to 20th	Night	18% 12% 3 7% 5% 3 5% 4 5% 6% 31%	1778
	21st to end	Night	22% 12% 3 6% 5% 4 4 3 4 5% 32%	1800
May	1st to 10th	Night	22% 10% 4 8% 6% 4 4 3 5% 6% 28%	3848
	11th to 20th	Night	22% 9% 4 8% 5% 4 4 3 6% 6% 28%	3444
	21st to end	Night	21% 9% 3 8% 5% 4 3 4 6% 6% 30%	3446
June	1st to 10th	Night	22% 9% 3 7% 5% 5% 5% 3 7% 7% 27%	1400
	11th to 20th	Night	21% 9% 2 6% 4 5% 5% 3 5% 6% 34%	1400
	21st to end	Night	21% 9% 3 8% 5% 4 5% 4 5% 6% 29%	1400
July	1st to 10th	Night	19% 7% 3 9% 5% 5% 6% 4 6% 6% 31%	3160
	11th to 20th	Night	13% 7% 3 7% 6% 6% 6% 5% 7% 10% 30%	3160
	21st to end	Night	16% 6% 2 7% 4 5% 5% 3 7% 8% 35%	3505
August	1st to 10th	Night	16% 8% 3 9% 6% 5% 6% 5% 7% 9% 27%	2845
	11th to 20th	Night	14% 7% 3 9% 6% 6% 6% 5% 6% 7% 30%	2872
	21st to end	Night	19% 6% 2 5% 4 3 3 3 5% 6% 44%	3223
September	1st to 10th	Night	21% 5% 2 6% 5% 4 5% 3 5% 7% 36%	1945
	11th to 20th	Night	22% 8% 2 7% 4 4 4 3 4 5% 38%	2191
	21st to end	Night	21% 6% 2 6% 4 3 4 3 5% 5% 41%	2200
October	1st to 10th	Night	20% 9% 2 7% 4 4 4 4 5% 6% 34%	2380
	11th to 20th	Night	29% 11% 3 7% 4 4 3 3 4 5% 27%	2400
	21st to end	Night	24% 15% 3 7% 4 5% 4 5% 4 6% 23%	2845
November	1st to 10th	Night	23% 19% 5% 9% 5% 4 5% 4 4 5% 17%	2853
	11th to 20th	Night	23% 22% 7% 10% 5% 3 3 3 3 5% 17%	2940
	21st to end	Night	19% 23% 8% 15% 6% 4 4 4 3 3 11%	2982
December	1st to 10th	Night	11% 21% 14% 26% 7% 5% 3 2 2 3 5%	5060
	11th to 20th	Night	15% 18% 7% 21% 11% 6% 4 3 3 4 9%	5741
	21st to end	Night	13% 19% 6% 17% 12% 5% 4 3 4 4 13%	7667

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	86% 4 6% 2 1	4094
	11th to 20th	Day	82% 5% 7% 5% 2	4110
	21st to end	Day	68% 9% 9% 10% 4	5122
February	1st to 10th	Day	68% 6% 8% 13% 5% 1	1866
	11th to 20th	Day	71% 5% 8% 11% 4	1851
	21st to end	Day	63% 6% 9% 18% 5%	1618
March	1st to 10th	Day	70% 5% 8% 13% 4	4762
	11th to 20th	Day	69% 6% 8% 12% 4	5057
	21st to end	Day	68% 4 5% 14% 7% 1	5466
April	1st to 10th	Day	65% 4 8% 14% 8% 1	2428
	11th to 20th	Day	57% 4 9% 20% 10% 1	2572
	21st to end	Day	57% 5% 11% 17% 9% 1	2600
May	1st to 10th	Day	57% 6% 10% 20% 6% 1	6099
	11th to 20th	Day	53% 6% 16% 18% 6%	6503
	21st to end	Day	51% 7% 12% 21% 8%	7451
June	1st to 10th	Day	54% 7% 11% 18% 9% 1	3000
	11th to 20th	Day	49% 7% 14% 19% 11% 1	3000
	21st to end	Day	54% 6% 13% 17% 9%	3000
July	1st to 10th	Day	48% 6% 13% 25% 7%	6745
	11th to 20th	Day	47% 8% 20% 19% 5%	6739
	21st to end	Day	39% 7% 21% 25% 8%	7138
August	1st to 10th	Day	43% 7% 22% 25% 4	4259
	11th to 20th	Day	49% 9% 22% 16% 4	4214
	21st to end	Day	42% 7% 20% 24% 7%	4675
September	1st to 10th	Day	48% 5% 18% 22% 7%	2455
	11th to 20th	Day	48% 4 18% 25% 6%	2205
	21st to end	Day	52% 5% 14% 23% 6%	2200
October	1st to 10th	Day	51% 7% 15% 20% 6%	3279
	11th to 20th	Day	62% 6% 11% 18% 3	3240
	21st to end	Day	65% 5% 11% 14% 4	3191
November	1st to 10th	Day	72% 5% 11% 9% 3	1665
	11th to 20th	Day	75% 4 10% 9% 2	1680
	21st to end	Day	82% 3 8% 5% 1	1633
December	1st to 10th	Day	86% 3 6% 4	2350
	11th to 20th	Day	80% 5% 5% 6% 3	2688
	21st to end	Day	73% 7% 8% 10% 3	3553
January	1st to 10th	Night	86% 4 7% 2	8831
	11th to 20th	Night	79% 6% 7% 7% 3	8880
	21st to end	Night	75% 6% 7% 8% 3 1	9057
February	1st to 10th	Night	69% 6% 7% 11% 5% 1	2753
	11th to 20th	Night	74% 5% 6% 11% 3	2666
	21st to end	Night	64% 6% 8% 15% 6%	2186
March	1st to 10th	Night	67% 6% 7% 14% 6%	5310
	11th to 20th	Night	72% 6% 7% 9% 5% 1	5058
	21st to end	Night	72% 4 6% 12% 6%	5466
April	1st to 10th	Night	68% 4 7% 11% 9% 1	1970
	11th to 20th	Night	54% 6% 8% 18% 13% 1	1778
	21st to end	Night	56% 5% 8% 18% 11% 2	1800
May	1st to 10th	Night	55% 8% 11% 14% 9% 2	3854
	11th to 20th	Night	54% 6% 12% 20% 8%	3445
	21st to end	Night	51% 8% 11% 21% 8%	3447
June	1st to 10th	Night	55% 5% 10% 20% 10% 1	1400
	11th to 20th	Night	50% 6% 12% 19% 13% 1	1400
	21st to end	Night	55% 6% 12% 17% 10% 1	1400
July	1st to 10th	Night	52% 6% 13% 24% 6%	3125
	11th to 20th	Night	47% 9% 20% 21% 3	3118
	21st to end	Night	45% 8% 19% 18% 9%	3401
August	1st to 10th	Night	50% 8% 18% 19% 4	2835
	11th to 20th	Night	50% 9% 20% 16% 4	2899
	21st to end	Night	41% 7% 15% 27% 10%	3223
September	1st to 10th	Night	48% 6% 12% 25% 8%	1945
	11th to 20th	Night	50% 5% 15% 22% 7%	2191
	21st to end	Night	47% 5% 13% 24% 11%	2200
October	1st to 10th	Night	50% 6% 14% 22% 8% 1	3887
	11th to 20th	Night	59% 5% 12% 19% 5%	3899
	21st to end	Night	63% 6% 11% 15% 4	4595
November	1st to 10th	Night	71% 5% 11% 9% 4	2853
	11th to 20th	Night	75% 4 9% 9% 3	2940
	21st to end	Night	80% 5% 8% 6% 1	2982
December	1st to 10th	Night	86% 4 7% 3 1	5060
	11th to 20th	Night	79% 8% 5% 7% 1	5742
	21st to end	Night	72% 6% 8% 11% 2	7667

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	26% 26% 26% 18% 3	220
	11th to 20th	Day	29% 26% 27% 11% 5% 1	220
	21st to end	Day	21% 31% 28% 15% 4 1	242
February	1st to 10th	Day	21% 24% 30% 16% 7% 2	406
	11th to 20th	Day	26% 27% 29% 13% 5%	426
	21st to end	Day	23% 26% 31% 12% 6% 1	388
March	1st to 10th	Day	26% 22% 32% 14% 4	540
	11th to 20th	Day	34% 18% 26% 14% 6% 1	528
	21st to end	Day	32% 25% 25% 11% 4 2	550
April	1st to 10th	Day	34% 22% 27% 11% 5% 1	500
	11th to 20th	Day	31% 19% 29% 14% 5% 1	492
	21st to end	Day	32% 18% 27% 14% 7% 2	500
May	1st to 10th	Day	35% 13% 29% 16% 6% 1	588
	11th to 20th	Day	29% 16% 27% 19% 8% 2	724
	21st to end	Day	33% 17% 27% 17% 5% 1	790
June	1st to 10th	Day	26% 15% 28% 22% 8% 2	730
	11th to 20th	Day	28% 16% 25% 20% 10% 1	730
	21st to end	Day	28% 13% 28% 24% 6% 2	730
July	1st to 10th	Day	24% 13% 29% 24% 8% 2	720
	11th to 20th	Day	21% 14% 30% 25% 8% 1	718
	21st to end	Day	20% 12% 32% 24% 10% 1	766
August	1st to 10th	Day	22% 11% 33% 24% 8% 2	526
	11th to 20th	Day	19% 11% 32% 26% 10% 2	519
	21st to end	Day	22% 11% 31% 23% 10% 3	583
September	1st to 10th	Day	26% 18% 25% 21% 7% 2	530
	11th to 20th	Day	32% 13% 27% 18% 6% 3	530
	21st to end	Day	32% 17% 28% 16% 6% 2	530
October	1st to 10th	Day	29% 22% 24% 16% 7% 2	430
	11th to 20th	Day	39% 16% 20% 16% 5% 2	420
	21st to end	Day	41% 19% 20% 13% 6%	462
November	1st to 10th	Day	42% 22% 22% 12% 2	425
	11th to 20th	Day	36% 23% 23% 10% 6% 1	430
	21st to end	Day	37% 24% 25% 10% 4 1	383
December	1st to 10th	Day	30% 23% 29% 12% 6% 1	220
	11th to 20th	Day	34% 23% 29% 12% 2	220
	21st to end	Day	29% 21% 32% 14% 2 1	242
January	1st to 10th	Night	29% 20% 28% 18% 5%	950
	11th to 20th	Night	25% 24% 28% 16% 6% 1	950
	21st to end	Night	19% 25% 28% 21% 7% 1	924
February	1st to 10th	Night	17% 24% 30% 19% 8% 1	840
	11th to 20th	Night	27% 20% 24% 21% 7% 1	823
	21st to end	Night	19% 19% 31% 20% 9% 2	692
March	1st to 10th	Night	22% 21% 28% 20% 8% 1	840
	11th to 20th	Night	30% 18% 23% 21% 7% 1	829
	21st to end	Night	28% 17% 24% 22% 8% 1	880
April	1st to 10th	Night	30% 17% 28% 18% 7% 1	675
	11th to 20th	Night	28% 16% 23% 22% 11% 1	594
	21st to end	Night	33% 12% 21% 24% 9% 2	600
May	1st to 10th	Night	33% 8% 21% 27% 9% 2	600
	11th to 20th	Night	25% 10% 26% 26% 12% 2	531
	21st to end	Night	28% 10% 29% 25% 7%	433
June	1st to 10th	Night	23% 8% 23% 35% 11% 1	400
	11th to 20th	Night	24% 10% 23% 27% 16% 1	400
	21st to end	Night	26% 9% 27% 28% 10% 1	400
July	1st to 10th	Night	22% 7% 27% 32% 10% 1	390
	11th to 20th	Night	14% 9% 28% 35% 14% 1	388
	21st to end	Night	19% 9% 21% 32% 17% 3	438
August	1st to 10th	Night	19% 8% 23% 33% 17% 1	553
	11th to 20th	Night	17% 7% 21% 35% 18% 2	592
	21st to end	Night	22% 8% 23% 29% 16% 2	660
September	1st to 10th	Night	26% 14% 20% 28% 12% 1	600
	11th to 20th	Night	29% 10% 21% 28% 12% 1	791
	21st to end	Night	28% 14% 24% 26% 9%	800
October	1st to 10th	Night	30% 16% 21% 24% 8% 1	800
	11th to 20th	Night	39% 14% 17% 20% 10% 1	800
	21st to end	Night	36% 16% 22% 17% 8% 1	880
November	1st to 10th	Night	39% 21% 23% 14% 3 1	919
	11th to 20th	Night	39% 18% 21% 15% 6% 1	950
	21st to end	Night	33% 22% 24% 13% 7%	950
December	1st to 10th	Night	27% 23% 28% 15% 5% 1	950
	11th to 20th	Night	35% 23% 24% 13% 5% 1	950
	21st to end	Night	28% 22% 24% 19% 4 2	1045

Page generated at 2026-03-15 02:23:53. Version ac07

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