Sainte-Scholastique
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sainte-Scholastique clear sky chart from 2005-11-06 to 2025-12-03.

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	17% 10% 3 8% 5% 5% 5% 4 5% 7% 32%	127302
	Night	17% 11% 4 9% 5% 4 4 3 5% 6% 31%	123423
Transparency	Day	49% 7% 13% 20% 10% 1	130747
	Night	52% 7% 12% 18% 10% 1	128065
Seeing	Day	21% 15% 31% 22% 9% 2	15876
	Night	21% 11% 31% 27% 9% 1	24859

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	16% 18% 6% 14% 5% 4 4 3 4 4 23%	3597
	11th to 20th	Day	13% 15% 6% 11% 7% 5% 4 3 5% 6% 26%	3570
	21st to end	Day	10% 17% 5% 11% 5% 5% 6% 4 5% 6% 26%	3960
February	1st to 10th	Day	13% 16% 5% 10% 6% 5% 6% 4 5% 5% 26%	1771
	11th to 20th	Day	14% 12% 5% 10% 7% 6% 4 5% 6% 6% 27%	1838
	21st to end	Day	18% 15% 5% 8% 5% 4 4 4 4 5% 27%	1650
March	1st to 10th	Day	19% 14% 5% 11% 6% 5% 4 3 4 4 25%	4476
	11th to 20th	Day	10% 14% 4 10% 5% 4 4 4 6% 7% 32%	4743
	21st to end	Day	19% 9% 4 9% 5% 4 4 3 4 4 35%	5939
April	1st to 10th	Day	21% 11% 3 7% 5% 4 4 4 4 5% 33%	2400
	11th to 20th	Day	21% 8% 3 6% 5% 5% 4 3 5% 5% 36%	2374
	21st to end	Day	22% 10% 3 7% 5% 5% 4 3 5% 6% 32%	2546
May	1st to 10th	Day	26% 10% 3 9% 5% 5% 4 4 5% 6% 22%	6334
	11th to 20th	Day	20% 9% 3 8% 5% 5% 4 4 5% 7% 31%	6318
	21st to end	Day	22% 8% 2 6% 4 4 4 4 6% 7% 31%	6949
June	1st to 10th	Day	20% 8% 2 7% 5% 5% 5% 4 6% 7% 30%	2800
	11th to 20th	Day	14% 6% 2 7% 5% 5% 5% 5% 6% 7% 38%	2800
	21st to end	Day	19% 8% 3 7% 6% 5% 5% 5% 6% 8% 29%	2800
July	1st to 10th	Day	13% 6% 3 8% 6% 6% 6% 5% 6% 8% 33%	6360
	11th to 20th	Day	11% 6% 2 6% 5% 5% 5% 4 7% 9% 40%	6360
	21st to end	Day	10% 5% 2 5% 3 4 5% 4 6% 9% 46%	6926
August	1st to 10th	Day	13% 6% 2 7% 5% 6% 5% 5% 7% 9% 35%	4563
	11th to 20th	Day	13% 7% 3 8% 4 4 5% 4 6% 8% 38%	4124
	21st to end	Day	15% 5% 2 6% 5% 5% 5% 4 6% 9% 39%	4312
September	1st to 10th	Day	12% 5% 2 6% 4 5% 5% 4 6% 9% 42%	2400
	11th to 20th	Day	12% 5% 3 4 3 5% 4 3 4 7% 51%	2330
	21st to end	Day	17% 5% 2 7% 4 4 3 4 5% 7% 43%	2200
October	1st to 10th	Day	19% 7% 3 6% 4 4 4 4 5% 6% 39%	2040
	11th to 20th	Day	19% 7% 3 8% 6% 5% 6% 4 5% 6% 31%	1970
	21st to end	Day	23% 9% 3 7% 5% 4 4 4 6% 6% 29%	1980
November	1st to 10th	Day	15% 10% 3 8% 4 5% 5% 3 5% 7% 33%	1851
	11th to 20th	Day	18% 9% 5% 7% 5% 5% 6% 4 5% 6% 30%	1779
	21st to end	Day	22% 11% 3 7% 5% 7% 5% 4 5% 6% 24%	1680
December	1st to 10th	Day	20% 18% 6% 12% 4 4 4 4 5% 4 19%	2616
	11th to 20th	Day	18% 15% 5% 10% 5% 4 3 3 5% 4 28%	2986
	21st to end	Day	23% 13% 5% 9% 5% 4 5% 4 4 4 24%	3960
January	1st to 10th	Night	13% 20% 7% 14% 5% 4 4 3 4 5% 21%	6349
	11th to 20th	Night	10% 15% 6% 16% 7% 6% 5% 3 5% 5% 21%	6315
	21st to end	Night	12% 15% 5% 12% 7% 5% 5% 4 5% 5% 25%	6996
February	1st to 10th	Night	14% 14% 5% 11% 6% 5% 5% 4 6% 6% 26%	2625
	11th to 20th	Night	13% 11% 4 9% 6% 6% 5% 4 6% 6% 30%	2448
	21st to end	Night	14% 16% 5% 9% 5% 4 4 3 4 5% 32%	1980
March	1st to 10th	Night	22% 14% 3 7% 5% 4 4 3 4 5% 29%	5364
	11th to 20th	Night	13% 14% 4 8% 5% 5% 5% 3 6% 7% 30%	5214
	21st to end	Night	15% 11% 3 9% 6% 5% 5% 3 5% 4 33%	4992
April	1st to 10th	Night	23% 10% 3 6% 5% 3 4 3 5% 6% 32%	2000
	11th to 20th	Night	21% 9% 3 6% 5% 4 3 3 5% 6% 35%	1975
	21st to end	Night	21% 8% 4 7% 3 3 4 4 4 6% 35%	1853
May	1st to 10th	Night	24% 9% 3 9% 5% 5% 5% 3 5% 6% 25%	3650
	11th to 20th	Night	22% 8% 3 6% 4 4 4 3 5% 6% 33%	3575
	21st to end	Night	19% 10% 4 8% 5% 4 4 3 5% 7% 31%	3926
June	1st to 10th	Night	19% 7% 3 7% 4 6% 5% 3 8% 8% 31%	1600
	11th to 20th	Night	15% 8% 2 6% 5% 3 4 4 5% 8% 39%	1600
	21st to end	Night	19% 7% 3 6% 5% 5% 5% 4 6% 6% 36%	1600
July	1st to 10th	Night	14% 6% 3 7% 5% 6% 6% 5% 8% 9% 32%	3600
	11th to 20th	Night	14% 6% 2 7% 4 4 5% 4 5% 7% 42%	3600
	21st to end	Night	10% 6% 2 6% 4 4 4 4 6% 9% 45%	3926
August	1st to 10th	Night	14% 7% 3 7% 5% 4 4 4 6% 7% 39%	2586
	11th to 20th	Night	15% 6% 3 7% 4 4 4 3 5% 6% 41%	2889
	21st to end	Night	17% 6% 2 6% 4 4 5% 4 5% 6% 40%	3586
September	1st to 10th	Night	10% 5% 3 7% 4 4 4 4 5% 8% 45%	2000
	11th to 20th	Night	13% 6% 2 4 3 3 3 3 5% 8% 50%	2069
	21st to end	Night	16% 5% 2 6% 4 4 4 3 5% 7% 44%	2200
October	1st to 10th	Night	18% 7% 3 5% 4 4 5% 3 5% 5% 42%	2356
	11th to 20th	Night	20% 8% 3 6% 5% 4 4 3 4 6% 37%	2429
	21st to end	Night	21% 8% 3 8% 5% 5% 4 4 4 5% 32%	2860
November	1st to 10th	Night	20% 9% 3 7% 4 5% 4 4 6% 7% 33%	2667
	11th to 20th	Night	17% 11% 3 8% 5% 4 5% 4 5% 6% 34%	2840
	21st to end	Night	20% 14% 3 9% 5% 4 3 4 4 5% 28%	2940
December	1st to 10th	Night	17% 16% 6% 10% 7% 6% 5% 4 5% 5% 20%	4609
	11th to 20th	Night	24% 13% 4 9% 5% 4 4 2 4 4 26%	5208
	21st to end	Night	25% 16% 4 9% 4 3 3 3 5% 5% 24%	6996

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	62% 8% 9% 16% 4	3598
	11th to 20th	Day	58% 7% 11% 16% 7% 1	3600
	21st to end	Day	57% 8% 11% 13% 10% 1	3960
February	1st to 10th	Day	59% 6% 10% 18% 6% 2	1771
	11th to 20th	Day	57% 7% 12% 14% 8% 1	1847
	21st to end	Day	59% 5% 10% 15% 9% 2	1650
March	1st to 10th	Day	60% 6% 8% 12% 10% 3	4479
	11th to 20th	Day	48% 9% 18% 13% 10% 2	4743
	21st to end	Day	50% 6% 8% 15% 18% 2	5939
April	1st to 10th	Day	53% 6% 9% 18% 12% 2	2400
	11th to 20th	Day	48% 6% 8% 21% 15% 2	2374
	21st to end	Day	53% 5% 10% 16% 13% 3	2546
May	1st to 10th	Day	59% 8% 9% 16% 7% 1	6345
	11th to 20th	Day	50% 9% 14% 17% 8% 2	6322
	21st to end	Day	49% 8% 13% 18% 12% 1	6949
June	1st to 10th	Day	50% 9% 10% 18% 12% 1	2800
	11th to 20th	Day	42% 8% 13% 21% 13% 3	2800
	21st to end	Day	50% 9% 13% 18% 9% 1	2800
July	1st to 10th	Day	46% 8% 13% 25% 8%	6290
	11th to 20th	Day	37% 8% 14% 29% 12%	6285
	21st to end	Day	34% 7% 15% 36% 9%	6728
August	1st to 10th	Day	44% 8% 17% 22% 8%	4549
	11th to 20th	Day	41% 8% 17% 27% 6%	4166
	21st to end	Day	40% 8% 17% 21% 13% 1	4312
September	1st to 10th	Day	36% 8% 16% 28% 12%	2400
	11th to 20th	Day	33% 7% 14% 31% 14% 1	2330
	21st to end	Day	41% 7% 14% 26% 11% 1	2200
October	1st to 10th	Day	44% 7% 13% 26% 10%	3326
	11th to 20th	Day	43% 6% 17% 26% 7%	3186
	21st to end	Day	44% 6% 20% 21% 9% 1	3180
November	1st to 10th	Day	49% 7% 14% 21% 7% 1	1851
	11th to 20th	Day	52% 8% 13% 17% 10%	1779
	21st to end	Day	59% 10% 12% 14% 5%	1680
December	1st to 10th	Day	69% 6% 9% 14% 2	2616
	11th to 20th	Day	60% 6% 10% 16% 9%	2986
	21st to end	Day	62% 6% 10% 15% 6%	3960
January	1st to 10th	Night	65% 7% 11% 12% 4	6349
	11th to 20th	Night	61% 9% 12% 12% 4	6360
	21st to end	Night	59% 7% 10% 10% 13% 1	6996
February	1st to 10th	Night	58% 8% 11% 15% 7% 1	2625
	11th to 20th	Night	52% 8% 13% 20% 7% 1	2450
	21st to end	Night	54% 6% 10% 17% 12% 1	1980
March	1st to 10th	Night	57% 6% 8% 13% 12% 4	5374
	11th to 20th	Night	49% 8% 14% 16% 10% 3	5215
	21st to end	Night	52% 6% 7% 21% 12% 2	4992
April	1st to 10th	Night	52% 6% 10% 18% 13% 2	2000
	11th to 20th	Night	51% 6% 8% 19% 14% 2	1975
	21st to end	Night	50% 6% 8% 18% 14% 4	1853
May	1st to 10th	Night	58% 7% 10% 16% 7% 2	3656
	11th to 20th	Night	49% 9% 11% 19% 10% 2	3576
	21st to end	Night	52% 7% 10% 16% 14% 1	3927
June	1st to 10th	Night	48% 10% 11% 18% 12% 1	1600
	11th to 20th	Night	42% 7% 12% 22% 15% 2	1600
	21st to end	Night	46% 9% 11% 20% 13% 1	1600
July	1st to 10th	Night	44% 8% 17% 21% 10%	3560
	11th to 20th	Night	39% 7% 16% 28% 10%	3552
	21st to end	Night	36% 6% 16% 29% 13%	3809
August	1st to 10th	Night	44% 7% 14% 27% 9%	2576
	11th to 20th	Night	42% 8% 18% 24% 8%	2913
	21st to end	Night	43% 8% 15% 21% 12% 1	3586
September	1st to 10th	Night	36% 8% 13% 26% 15% 1	2000
	11th to 20th	Night	34% 6% 14% 33% 12% 1	2069
	21st to end	Night	39% 8% 12% 26% 15%	2200
October	1st to 10th	Night	43% 6% 14% 25% 11% 1	3850
	11th to 20th	Night	43% 6% 13% 29% 9%	3952
	21st to end	Night	45% 6% 18% 18% 11% 1	4610
November	1st to 10th	Night	51% 6% 13% 21% 8% 1	2667
	11th to 20th	Night	51% 7% 14% 17% 10% 1	2840
	21st to end	Night	58% 7% 12% 16% 6%	2940
December	1st to 10th	Night	66% 6% 13% 12% 3	4609
	11th to 20th	Night	61% 6% 7% 15% 10%	5208
	21st to end	Night	62% 5% 8% 14% 11%	6996

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	20% 17% 41% 19% 4	200
	11th to 20th	Day	25% 18% 39% 13% 5% 1	200
	21st to end	Day	20% 20% 38% 17% 5%	220
February	1st to 10th	Day	27% 25% 36% 11% 1	286
	11th to 20th	Day	21% 24% 41% 12% 2	385
	21st to end	Day	29% 19% 32% 18% 2	414
March	1st to 10th	Day	27% 16% 34% 19% 4	500
	11th to 20th	Day	21% 23% 33% 18% 4 1	500
	21st to end	Day	26% 22% 29% 14% 9% 1	550
April	1st to 10th	Day	26% 20% 31% 16% 6% 1	500
	11th to 20th	Day	28% 22% 24% 17% 7% 1	492
	21st to end	Day	30% 17% 31% 16% 6% 2	500
May	1st to 10th	Day	27% 14% 34% 19% 5% 1	503
	11th to 20th	Day	21% 15% 33% 22% 7% 2	527
	21st to end	Day	21% 18% 31% 22% 8% 1	573
June	1st to 10th	Day	22% 16% 31% 22% 7% 1	530
	11th to 20th	Day	17% 15% 31% 25% 11% 2	530
	21st to end	Day	23% 12% 30% 24% 8% 2	530
July	1st to 10th	Day	13% 8% 34% 30% 12% 3	525
	11th to 20th	Day	13% 10% 32% 32% 11% 2	524
	21st to end	Day	13% 8% 31% 32% 13% 2	576
August	1st to 10th	Day	14% 7% 25% 34% 16% 3	526
	11th to 20th	Day	11% 8% 24% 34% 17% 7%	519
	21st to end	Day	16% 11% 27% 24% 15% 7%	583
September	1st to 10th	Day	15% 8% 32% 24% 16% 6%	530
	11th to 20th	Day	11% 9% 24% 25% 22% 9%	530
	21st to end	Day	18% 13% 26% 25% 14% 4	530
October	1st to 10th	Day	22% 12% 27% 24% 13% 2	530
	11th to 20th	Day	19% 16% 34% 20% 10% 1	513
	21st to end	Day	30% 14% 28% 21% 7%	462
November	1st to 10th	Day	28% 17% 29% 20% 5% 1	425
	11th to 20th	Day	23% 19% 35% 18% 5%	319
	21st to end	Day	29% 21% 30% 16% 3	220
December	1st to 10th	Day	25% 17% 27% 24% 4 1	204
	11th to 20th	Day	29% 19% 35% 15% 2 1	200
	21st to end	Day	30% 20% 26% 15% 6% 1	220
January	1st to 10th	Night	23% 13% 37% 23% 4	800
	11th to 20th	Night	25% 14% 33% 22% 6%	800
	21st to end	Night	16% 13% 39% 26% 6%	880
February	1st to 10th	Night	18% 14% 41% 22% 3 1	800
	11th to 20th	Night	20% 15% 42% 19% 4	783
	21st to end	Night	22% 14% 34% 27% 3	660
March	1st to 10th	Night	23% 14% 35% 24% 4	800
	11th to 20th	Night	22% 16% 34% 23% 5%	800
	21st to end	Night	22% 12% 35% 25% 6%	880
April	1st to 10th	Night	27% 15% 29% 25% 4	800
	11th to 20th	Night	23% 14% 33% 25% 5%	791
	21st to end	Night	27% 11% 35% 19% 7%	653
May	1st to 10th	Night	25% 9% 34% 24% 6% 2	430
	11th to 20th	Night	23% 9% 30% 28% 10%	394
	21st to end	Night	17% 9% 38% 27% 8%	433
June	1st to 10th	Night	24% 8% 30% 32% 8%	400
	11th to 20th	Night	21% 6% 30% 33% 10% 1	400
	21st to end	Night	22% 7% 27% 31% 14%	400
July	1st to 10th	Night	9% 6% 33% 37% 15%	390
	11th to 20th	Night	12% 5% 23% 42% 17%	388
	21st to end	Night	13% 4 26% 42% 13% 2	438
August	1st to 10th	Night	14% 3 19% 44% 19% 1	398
	11th to 20th	Night	13% 3 23% 35% 24% 3	592
	21st to end	Night	15% 6% 26% 34% 18% 2	880
September	1st to 10th	Night	12% 6% 28% 39% 15% 1	800
	11th to 20th	Night	15% 5% 22% 33% 23% 2	800
	21st to end	Night	18% 7% 26% 32% 16% 2	800
October	1st to 10th	Night	21% 8% 27% 32% 12% 1	800
	11th to 20th	Night	22% 12% 29% 29% 8% 1	800
	21st to end	Night	26% 11% 32% 26% 5%	880
November	1st to 10th	Night	24% 13% 30% 26% 6% 1	820
	11th to 20th	Night	23% 14% 33% 21% 9%	840
	21st to end	Night	28% 15% 31% 20% 6%	840
December	1st to 10th	Night	27% 12% 34% 22% 5%	809
	11th to 20th	Night	28% 17% 31% 20% 4 1	800
	21st to end	Night	33% 13% 31% 19% 4	880

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