Saint-Agapit
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saint-Agapit clear sky chart from 2005-11-06 to 2026-11-13.

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	18% 11% 4 9% 5% 5% 5% 4 5% 6% 30%	153321
	Night	17% 12% 4 10% 5% 4 4 3 5% 6% 28%	147740
Transparency	Day	52% 7% 13% 19% 8% 1	156779
	Night	56% 6% 12% 18% 8% 1	152373
Seeing	Day	25% 16% 29% 20% 8% 2	17740
	Night	25% 13% 30% 25% 7%	26259

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% 19% 6% 13% 6% 4 4 3 4 4 22%	4661
	11th to 20th	Day	11% 19% 8% 18% 9% 5% 4 2 3 3 17%	4650
	21st to end	Day	6% 13% 6% 13% 7% 6% 6% 6% 6% 7% 24%	5124
February	1st to 10th	Day	12% 16% 6% 13% 8% 5% 4 3 4 5% 24%	1683
	11th to 20th	Day	13% 17% 6% 12% 6% 5% 5% 3 4 5% 23%	2047
	21st to end	Day	12% 16% 6% 11% 6% 4 4 3 4 6% 27%	1730
March	1st to 10th	Day	19% 16% 6% 11% 5% 4 4 3 4 4 24%	4576
	11th to 20th	Day	15% 17% 5% 9% 5% 4 4 4 4 5% 28%	4846
	21st to end	Day	20% 14% 4 8% 4 3 4 3 4 4 31%	5956
April	1st to 10th	Day	23% 13% 4 9% 5% 4 4 3 4 5% 27%	2520
	11th to 20th	Day	20% 11% 3 7% 4 3 4 3 4 6% 35%	2583
	21st to end	Day	23% 11% 3 8% 4 4 4 3 4 5% 30%	2730
May	1st to 10th	Day	26% 10% 3 8% 4 4 4 3 5% 6% 26%	7812
	11th to 20th	Day	19% 8% 3 8% 5% 5% 5% 4 6% 7% 29%	8221
	21st to end	Day	20% 8% 3 8% 5% 5% 5% 4 6% 6% 30%	9060
June	1st to 10th	Day	20% 7% 2 7% 5% 6% 6% 4 6% 7% 29%	3122
	11th to 20th	Day	19% 7% 2 6% 4 4 4 4 6% 8% 34%	3150
	21st to end	Day	23% 8% 3 8% 5% 5% 5% 4 6% 7% 27%	3127
July	1st to 10th	Day	15% 7% 3 8% 5% 5% 5% 4 6% 9% 32%	8280
	11th to 20th	Day	13% 7% 2 7% 4 5% 5% 5% 7% 9% 37%	8280
	21st to end	Day	11% 7% 3 7% 5% 4 5% 4 7% 9% 38%	8993
August	1st to 10th	Day	15% 7% 3 7% 5% 5% 6% 5% 7% 9% 30%	6444
	11th to 20th	Day	18% 8% 3 8% 5% 6% 6% 5% 7% 8% 27%	5953
	21st to end	Day	18% 7% 2 7% 4 4 4 3 5% 7% 37%	6269
September	1st to 10th	Day	16% 6% 2 7% 5% 4 4 4 6% 8% 38%	2520
	11th to 20th	Day	16% 7% 2 5% 3 3 3 3 5% 6% 46%	2337
	21st to end	Day	19% 8% 3 7% 4 4 4 3 5% 6% 39%	2310
October	1st to 10th	Day	21% 11% 3 8% 5% 4 4 4 5% 6% 29%	3689
	11th to 20th	Day	26% 8% 3 8% 5% 4 5% 4 4 5% 30%	3086
	21st to end	Day	18% 10% 3 6% 4 3 4 3 4 5% 39%	3322
November	1st to 10th	Day	20% 13% 4 9% 6% 4 4 3 4 4 29%	1941
	11th to 20th	Day	21% 16% 4 10% 6% 3 4 3 4 5% 25%	1908
	21st to end	Day	23% 19% 5% 9% 5% 4 4 3 4 3 21%	1558
December	1st to 10th	Day	19% 16% 6% 12% 6% 5% 4 3 5% 5% 20%	2350
	11th to 20th	Day	20% 16% 6% 11% 5% 5% 3 3 3 4 25%	2688
	21st to end	Day	22% 16% 4 10% 5% 4 5% 4 5% 5% 21%	3795
January	1st to 10th	Night	15% 18% 6% 13% 6% 4 5% 3 5% 4 20%	8234
	11th to 20th	Night	11% 23% 9% 18% 7% 5% 4 3 3 3 13%	8235
	21st to end	Night	7% 12% 6% 15% 7% 7% 6% 5% 5% 6% 23%	9057
February	1st to 10th	Night	12% 15% 6% 12% 8% 5% 5% 4 4 5% 25%	2935
	11th to 20th	Night	13% 17% 5% 13% 7% 6% 3 3 4 4 24%	2458
	21st to end	Night	14% 17% 5% 9% 6% 4 4 3 5% 5% 29%	2076
March	1st to 10th	Night	21% 15% 4 10% 5% 4 5% 2 4 4 25%	5484
	11th to 20th	Night	16% 14% 4 10% 6% 6% 5% 4 5% 6% 24%	5332
	21st to end	Night	18% 16% 5% 9% 6% 4 3 3 4 4 28%	5215
April	1st to 10th	Night	22% 14% 5% 8% 4 3 4 3 5% 5% 28%	2100
	11th to 20th	Night	21% 11% 3 8% 5% 4 3 4 4 6% 31%	1985
	21st to end	Night	25% 10% 3 7% 5% 3 2 3 4 5% 33%	1890
May	1st to 10th	Night	24% 9% 3 9% 5% 4 5% 3 5% 6% 28%	5141
	11th to 20th	Night	23% 8% 3 7% 5% 4 5% 3 5% 7% 30%	4639
	21st to end	Night	21% 8% 3 7% 4 4 4 3 5% 7% 34%	5114
June	1st to 10th	Night	21% 9% 3 5% 5% 4 4 4 6% 7% 31%	1494
	11th to 20th	Night	18% 7% 3 7% 5% 4 5% 4 6% 7% 33%	1470
	21st to end	Night	20% 8% 2 8% 7% 4 5% 4 5% 6% 30%	1487
July	1st to 10th	Night	16% 8% 3 7% 5% 5% 5% 4 6% 9% 32%	4680
	11th to 20th	Night	18% 6% 2 6% 5% 4 4 4 6% 8% 37%	4680
	21st to end	Night	11% 6% 3 8% 6% 5% 5% 4 6% 8% 36%	5084
August	1st to 10th	Night	20% 9% 3 7% 5% 4 4 4 6% 8% 31%	3666
	11th to 20th	Night	16% 7% 3 7% 5% 5% 5% 5% 5% 8% 33%	4085
	21st to end	Night	17% 7% 3 7% 5% 5% 4 4 5% 6% 36%	4853
September	1st to 10th	Night	18% 6% 3 7% 4 4 3 4 5% 7% 40%	2100
	11th to 20th	Night	15% 6% 2 6% 3 3 3 4 4 6% 46%	2282
	21st to end	Night	18% 7% 2 6% 5% 4 4 3 5% 6% 41%	2310
October	1st to 10th	Night	18% 10% 3 6% 4 3 4 3 4 5% 40%	3705
	11th to 20th	Night	23% 8% 3 8% 4 4 4 3 4 5% 34%	4312
	21st to end	Night	16% 8% 2 6% 3 3 3 3 4 5% 45%	4818
November	1st to 10th	Night	20% 13% 4 9% 5% 4 4 3 4 7% 27%	2797
	11th to 20th	Night	19% 14% 5% 10% 5% 4 4 3 4 5% 28%	2757
	21st to end	Night	20% 19% 5% 10% 5% 4 3 3 3 5% 22%	3056
December	1st to 10th	Night	17% 16% 7% 14% 7% 6% 5% 4 4 4 17%	5060
	11th to 20th	Night	21% 17% 5% 12% 6% 4 4 3 4 4 22%	5741
	21st to end	Night	21% 18% 5% 8% 5% 4 4 3 3 4 24%	7408

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	65% 5% 9% 15% 6%	4662
	11th to 20th	Day	71% 6% 6% 12% 4 1	4680
	21st to end	Day	54% 8% 10% 16% 11%	5124
February	1st to 10th	Day	64% 4 8% 15% 7% 2	1683
	11th to 20th	Day	63% 5% 11% 13% 6% 1	2056
	21st to end	Day	58% 5% 10% 17% 8% 2	1730
March	1st to 10th	Day	62% 6% 9% 11% 9% 3	4579
	11th to 20th	Day	56% 7% 15% 14% 8%	4846
	21st to end	Day	56% 4 8% 16% 14% 3	5956
April	1st to 10th	Day	61% 4 9% 14% 9% 2	2520
	11th to 20th	Day	52% 5% 10% 20% 11% 2	2583
	21st to end	Day	56% 5% 10% 16% 11% 2	2730
May	1st to 10th	Day	56% 6% 10% 17% 9% 1	7824
	11th to 20th	Day	50% 10% 14% 18% 7% 2	8225
	21st to end	Day	51% 8% 11% 18% 10% 2	9061
June	1st to 10th	Day	52% 8% 11% 20% 7% 1	3122
	11th to 20th	Day	46% 8% 14% 21% 10% 1	3150
	21st to end	Day	56% 8% 11% 16% 9%	3127
July	1st to 10th	Day	45% 8% 15% 23% 9%	8210
	11th to 20th	Day	40% 8% 16% 27% 7%	8205
	21st to end	Day	41% 8% 18% 26% 7%	8795
August	1st to 10th	Day	47% 10% 18% 18% 6% 1	6430
	11th to 20th	Day	49% 11% 18% 17% 5%	5992
	21st to end	Day	44% 8% 16% 23% 9% 1	6269
September	1st to 10th	Day	43% 7% 15% 25% 9%	2520
	11th to 20th	Day	39% 5% 16% 29% 11%	2337
	21st to end	Day	46% 6% 13% 24% 11%	2310
October	1st to 10th	Day	54% 7% 13% 23% 3	5067
	11th to 20th	Day	54% 5% 16% 20% 4 2	4226
	21st to end	Day	46% 6% 14% 24% 10%	4520
November	1st to 10th	Day	59% 6% 12% 17% 7%	1941
	11th to 20th	Day	63% 5% 10% 16% 6%	1908
	21st to end	Day	68% 5% 13% 10% 3	1558
December	1st to 10th	Day	66% 5% 12% 11% 5%	2350
	11th to 20th	Day	64% 4 9% 15% 8%	2688
	21st to end	Day	64% 7% 9% 11% 8% 1	3795
January	1st to 10th	Night	66% 6% 10% 12% 5%	8234
	11th to 20th	Night	74% 6% 7% 10% 3	8280
	21st to end	Night	59% 7% 10% 14% 10%	9057
February	1st to 10th	Night	62% 5% 9% 17% 7% 1	2935
	11th to 20th	Night	63% 6% 9% 14% 8% 1	2460
	21st to end	Night	57% 4 10% 16% 11% 1	2076
March	1st to 10th	Night	62% 5% 9% 12% 10% 1	5494
	11th to 20th	Night	59% 7% 13% 13% 8% 1	5333
	21st to end	Night	59% 4 6% 20% 9% 1	5215
April	1st to 10th	Night	58% 5% 10% 14% 11% 2	2100
	11th to 20th	Night	54% 5% 8% 20% 11% 2	1985
	21st to end	Night	54% 4 8% 18% 14% 2	1890
May	1st to 10th	Night	56% 6% 12% 16% 10% 1	5147
	11th to 20th	Night	51% 7% 11% 21% 9% 1	4640
	21st to end	Night	50% 6% 11% 16% 16% 1	5115
June	1st to 10th	Night	49% 7% 11% 22% 10% 1	1494
	11th to 20th	Night	48% 8% 11% 20% 12% 2	1470
	21st to end	Night	52% 7% 13% 18% 9% 1	1487
July	1st to 10th	Night	46% 8% 17% 19% 9%	4640
	11th to 20th	Night	42% 8% 19% 24% 7%	4632
	21st to end	Night	43% 8% 17% 24% 7%	4967
August	1st to 10th	Night	50% 9% 16% 19% 6%	3656
	11th to 20th	Night	47% 10% 18% 20% 4	4112
	21st to end	Night	46% 8% 14% 21% 11%	4853
September	1st to 10th	Night	42% 8% 14% 24% 10% 1	2100
	11th to 20th	Night	39% 7% 16% 29% 9% 1	2282
	21st to end	Night	43% 7% 12% 24% 14%	2310
October	1st to 10th	Night	47% 6% 12% 27% 7%	5108
	11th to 20th	Night	51% 5% 12% 26% 5% 1	5913
	21st to end	Night	41% 5% 15% 23% 14% 2	6568
November	1st to 10th	Night	57% 6% 13% 18% 5%	2797
	11th to 20th	Night	59% 5% 12% 15% 8%	2757
	21st to end	Night	66% 5% 11% 12% 5%	3056
December	1st to 10th	Night	70% 6% 10% 11% 2	5060
	11th to 20th	Night	65% 6% 8% 17% 5%	5742
	21st to end	Night	64% 5% 8% 15% 7%	7408

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	34% 23% 27% 15% 1 1	220
	11th to 20th	Day	26% 28% 31% 9% 5%	220
	21st to end	Day	22% 24% 35% 14% 4	242
February	1st to 10th	Day	23% 26% 35% 12% 3 1	223
	11th to 20th	Day	26% 23% 35% 14% 2	535
	21st to end	Day	24% 25% 32% 15% 3	446
March	1st to 10th	Day	31% 21% 28% 16% 4	540
	11th to 20th	Day	29% 21% 30% 15% 5% 1	540
	21st to end	Day	29% 21% 28% 15% 6% 2	594
April	1st to 10th	Day	34% 18% 28% 15% 5%	540
	11th to 20th	Day	31% 18% 27% 17% 5% 1	532
	21st to end	Day	31% 18% 30% 13% 6% 1	540
May	1st to 10th	Day	31% 17% 31% 17% 3 1	543
	11th to 20th	Day	23% 14% 32% 21% 9% 1	567
	21st to end	Day	24% 21% 32% 16% 7%	617
June	1st to 10th	Day	22% 13% 32% 24% 7% 1	752
	11th to 20th	Day	23% 13% 29% 24% 11% 1	780
	21st to end	Day	26% 11% 27% 23% 11% 1	757
July	1st to 10th	Day	17% 14% 32% 25% 11% 2	565
	11th to 20th	Day	18% 14% 35% 23% 8% 2	564
	21st to end	Day	18% 11% 32% 27% 10% 2	620
August	1st to 10th	Day	18% 11% 27% 30% 11% 4	566
	11th to 20th	Day	20% 6% 26% 28% 16% 3	559
	21st to end	Day	21% 15% 25% 20% 13% 5%	627
September	1st to 10th	Day	19% 13% 27% 25% 11% 4	570
	11th to 20th	Day	18% 12% 26% 24% 15% 5%	570
	21st to end	Day	21% 14% 25% 22% 14% 4	570
October	1st to 10th	Day	24% 15% 28% 22% 9% 2	570
	11th to 20th	Day	29% 17% 27% 18% 8% 1	474
	21st to end	Day	33% 16% 26% 20% 5%	495
November	1st to 10th	Day	34% 16% 30% 15% 5% 1	455
	11th to 20th	Day	29% 20% 28% 15% 7% 1	436
	21st to end	Day	38% 19% 28% 13% 2	229
December	1st to 10th	Day	31% 16% 30% 16% 6%	220
	11th to 20th	Day	34% 22% 29% 12% 3 1	220
	21st to end	Day	31% 23% 29% 13% 2 1	242
January	1st to 10th	Night	27% 18% 34% 17% 3	840
	11th to 20th	Night	27% 18% 33% 20% 3	840
	21st to end	Night	16% 15% 36% 27% 5%	924
February	1st to 10th	Night	20% 15% 36% 24% 5%	840
	11th to 20th	Night	23% 19% 37% 18% 3	823
	21st to end	Night	25% 15% 33% 24% 3	692
March	1st to 10th	Night	27% 15% 35% 20% 3	840
	11th to 20th	Night	28% 15% 33% 18% 5%	840
	21st to end	Night	25% 14% 32% 23% 6%	924
April	1st to 10th	Night	31% 15% 30% 19% 4	840
	11th to 20th	Night	27% 13% 33% 22% 5%	741
	21st to end	Night	30% 14% 29% 21% 6%	630
May	1st to 10th	Night	28% 10% 32% 25% 5%	589
	11th to 20th	Night	23% 13% 29% 31% 4 1	414
	21st to end	Night	23% 11% 32% 29% 6%	455
June	1st to 10th	Night	25% 7% 30% 33% 6%	420
	11th to 20th	Night	21% 8% 26% 37% 8%	420
	21st to end	Night	23% 7% 29% 33% 8%	420
July	1st to 10th	Night	17% 6% 35% 34% 9%	410
	11th to 20th	Night	18% 6% 26% 38% 12% 1	408
	21st to end	Night	13% 8% 24% 46% 8%	460
August	1st to 10th	Night	17% 4 22% 40% 16%	418
	11th to 20th	Night	17% 6% 24% 38% 14% 1	615
	21st to end	Night	18% 8% 27% 32% 15% 1	833
September	1st to 10th	Night	20% 6% 27% 33% 12% 1	840
	11th to 20th	Night	19% 8% 24% 32% 17% 2	840
	21st to end	Night	20% 8% 28% 28% 14% 1	840
October	1st to 10th	Night	23% 10% 27% 32% 8% 1	840
	11th to 20th	Night	28% 11% 30% 23% 8% 1	840
	21st to end	Night	30% 13% 31% 20% 5%	924
November	1st to 10th	Night	29% 16% 27% 22% 6%	860
	11th to 20th	Night	26% 16% 29% 20% 9% 1	849
	21st to end	Night	31% 18% 28% 17% 6% 1	906
December	1st to 10th	Night	31% 15% 30% 19% 6%	950
	11th to 20th	Night	28% 20% 27% 19% 5% 1	950
	21st to end	Night	33% 17% 31% 16% 3 1	984

Page generated at 2026-11-10 03:55:20. Version ac07

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