Observatoire Maucar de La Motte
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatoire Maucar de La Motte clear sky chart from 2005-11-06 to 2024-03-28.

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	19% 12% 5% 8% 7% 4 5% 5% 5% 6% 25%	78366
	Night	17% 14% 6% 10% 8% 4 5% 5% 4 5% 23%	81646
Transparency	Day	60% 6% 10% 16% 7% 1	78061
	Night	63% 6% 10% 14% 7% 1	81486
Seeing	Day	24% 16% 33% 19% 7% 2	14171
	Night	25% 13% 31% 23% 7% 1	23280

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	15% 21% 9% 13% 6% 6% 8% 5% 5% 5% 8%	2208
	11th to 20th	Day	10% 14% 9% 18% 11% 3 6% 7% 5% 5% 13%	2253
	21st to end	Day	13% 19% 9% 15% 8% 4 5% 4 4 5% 15%	2904
February	1st to 10th	Day	9% 15% 7% 12% 10% 7% 9% 5% 4 7% 17%	1710
	11th to 20th	Day	11% 18% 6% 12% 8% 4 7% 6% 5% 5% 18%	1663
	21st to end	Day	13% 15% 7% 12% 8% 5% 4 5% 4 5% 22%	1429
March	1st to 10th	Day	15% 13% 6% 10% 7% 5% 6% 5% 4 5% 24%	1996
	11th to 20th	Day	13% 15% 6% 10% 7% 4 4 4 4 5% 29%	2090
	21st to end	Day	14% 14% 5% 8% 6% 4 4 4 3 6% 30%	2296
April	1st to 10th	Day	21% 15% 6% 8% 7% 3 4 5% 4 5% 23%	2160
	11th to 20th	Day	20% 10% 4 7% 6% 3 4 4 4 5% 32%	2230
	21st to end	Day	22% 11% 4 6% 5% 3 4 4 4 6% 31%	2358
May	1st to 10th	Day	18% 10% 3 6% 6% 3 6% 6% 5% 6% 31%	2520
	11th to 20th	Day	22% 10% 3 6% 5% 3 5% 4 5% 6% 32%	2478
	21st to end	Day	19% 8% 3 6% 6% 3 5% 4 5% 6% 35%	2725
June	1st to 10th	Day	21% 8% 3 6% 6% 3 5% 5% 6% 8% 29%	2695
	11th to 20th	Day	16% 7% 3 7% 6% 3 6% 5% 5% 7% 35%	2700
	21st to end	Day	19% 6% 4 6% 6% 4 6% 5% 5% 7% 32%	2700
July	1st to 10th	Day	18% 5% 3 5% 6% 3 5% 6% 6% 9% 33%	2700
	11th to 20th	Day	16% 7% 3 6% 5% 3 6% 6% 7% 8% 32%	2700
	21st to end	Day	17% 7% 3 6% 6% 4 5% 6% 7% 9% 30%	2755
August	1st to 10th	Day	19% 8% 3 7% 7% 4 5% 6% 6% 8% 28%	2446
	11th to 20th	Day	20% 7% 3 6% 6% 3 5% 5% 6% 7% 31%	2303
	21st to end	Day	18% 7% 4 7% 6% 3 6% 4 6% 8% 31%	2496
September	1st to 10th	Day	20% 7% 3 5% 5% 3 5% 6% 6% 7% 32%	2160
	11th to 20th	Day	22% 9% 3 5% 6% 3 5% 5% 5% 7% 30%	2150
	21st to end	Day	24% 10% 4 5% 5% 2 4 4 5% 5% 31%	1886
October	1st to 10th	Day	23% 13% 2 7% 5% 3 4 5% 4 5% 30%	1800
	11th to 20th	Day	32% 20% 4 6% 4 2 3 3 4 4 17%	1800
	21st to end	Day	29% 18% 4 7% 6% 3 5% 4 4 5% 15%	1859
November	1st to 10th	Day	21% 20% 7% 11% 5% 3 4 3 3 5% 17%	1486
	11th to 20th	Day	22% 17% 9% 13% 9% 4 4 4 3 4 12%	1520
	21st to end	Day	25% 22% 9% 12% 8% 3 4 3 3 3 8%	1520
December	1st to 10th	Day	18% 22% 9% 13% 7% 3 4 3 4 4 11%	1520
	11th to 20th	Day	17% 18% 7% 11% 9% 5% 5% 5% 4 4 14%	1719
	21st to end	Day	18% 21% 7% 15% 12% 4 4 4 3 3 10%	2431
January	1st to 10th	Night	14% 17% 9% 16% 10% 5% 6% 5% 4 3 11%	4748
	11th to 20th	Night	11% 15% 6% 15% 11% 5% 7% 6% 4 5% 14%	4714
	21st to end	Night	10% 17% 11% 14% 10% 7% 7% 5% 4 4 12%	4748
February	1st to 10th	Night	11% 15% 6% 10% 10% 5% 7% 6% 6% 6% 19%	2470
	11th to 20th	Night	12% 17% 6% 12% 9% 5% 5% 5% 4 6% 20%	2403
	21st to end	Night	10% 15% 7% 12% 9% 5% 7% 5% 4 6% 19%	2023
March	1st to 10th	Night	13% 13% 6% 11% 7% 4 7% 6% 5% 6% 23%	2170
	11th to 20th	Night	17% 15% 7% 9% 7% 4 6% 5% 4 4 23%	2089
	21st to end	Night	14% 12% 4 8% 6% 3 4 4 4 5% 34%	2214
April	1st to 10th	Night	20% 14% 5% 9% 5% 3 3 4 4 5% 28%	1800
	11th to 20th	Night	18% 9% 3 7% 5% 3 5% 5% 5% 6% 31%	1696
	21st to end	Night	19% 11% 4 6% 4 3 4 4 5% 6% 34%	1602
May	1st to 10th	Night	16% 11% 3 6% 5% 3 4 3 5% 7% 35%	1440
	11th to 20th	Night	21% 7% 3 6% 6% 2 4 5% 5% 7% 34%	1415
	21st to end	Night	20% 7% 3 6% 5% 3 4 4 6% 7% 36%	1550
June	1st to 10th	Night	21% 6% 4 6% 6% 4 6% 5% 6% 6% 30%	1260
	11th to 20th	Night	17% 6% 3 6% 6% 3 4 5% 5% 7% 38%	1260
	21st to end	Night	15% 5% 3 6% 6% 3 5% 5% 7% 8% 38%	1260
July	1st to 10th	Night	18% 5% 3 4 5% 3 5% 6% 6% 10% 34%	1260
	11th to 20th	Night	15% 5% 3 4 5% 3 5% 5% 7% 8% 39%	1260
	21st to end	Night	14% 6% 3 6% 6% 4 5% 5% 5% 9% 37%	1560
August	1st to 10th	Night	17% 5% 2 6% 6% 3 6% 4 5% 8% 36%	1489
	11th to 20th	Night	16% 5% 3 5% 6% 4 5% 4 5% 8% 39%	1598
	21st to end	Night	17% 8% 3 7% 6% 3 5% 4 6% 6% 35%	1841
September	1st to 10th	Night	19% 7% 3 6% 5% 3 5% 4 5% 6% 38%	1800
	11th to 20th	Night	21% 8% 3 5% 6% 2 4 3 5% 6% 37%	1808
	21st to end	Night	22% 9% 3 5% 5% 2 4 3 4 6% 35%	2074
October	1st to 10th	Night	23% 9% 3 6% 6% 3 4 4 4 5% 31%	2160
	11th to 20th	Night	29% 16% 4 8% 6% 3 3 3 4 4 19%	2160
	21st to end	Night	26% 19% 5% 7% 6% 3 3 4 4 5% 18%	2493
November	1st to 10th	Night	19% 16% 7% 10% 6% 3 4 4 4 5% 21%	2592
	11th to 20th	Night	21% 16% 7% 13% 8% 4 4 4 4 4 16%	2660
	21st to end	Night	24% 19% 7% 13% 9% 3 4 3 4 4 10%	2660
December	1st to 10th	Night	18% 22% 8% 14% 8% 5% 4 4 3 4 11%	2660
	11th to 20th	Night	18% 19% 6% 12% 10% 4 6% 4 4 3 13%	3473
	21st to end	Night	19% 19% 11% 15% 10% 3 4 3 2 3 12%	5236

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	78% 6% 9% 6% 1	2209
	11th to 20th	Day	72% 5% 6% 13% 3	2253
	21st to end	Day	73% 3 7% 12% 5%	2904
February	1st to 10th	Day	68% 5% 6% 14% 7%	1710
	11th to 20th	Day	68% 5% 7% 13% 6%	1672
	21st to end	Day	64% 4 8% 16% 7% 1	1429
March	1st to 10th	Day	63% 5% 6% 14% 11% 1	1999
	11th to 20th	Day	59% 5% 8% 18% 9% 1	2090
	21st to end	Day	56% 4 8% 19% 11% 3	2296
April	1st to 10th	Day	63% 5% 9% 12% 10% 1	2160
	11th to 20th	Day	54% 5% 9% 19% 11% 2	2230
	21st to end	Day	55% 4 8% 16% 14% 2	2358
May	1st to 10th	Day	52% 7% 10% 17% 12% 2	2520
	11th to 20th	Day	53% 7% 9% 18% 13% 1	2482
	21st to end	Day	50% 7% 10% 20% 13% 1	2725
June	1st to 10th	Day	52% 7% 10% 20% 10% 1	2695
	11th to 20th	Day	48% 7% 9% 23% 12% 2	2700
	21st to end	Day	50% 8% 12% 22% 9% 1	2700
July	1st to 10th	Day	46% 8% 14% 24% 7% 1	2626
	11th to 20th	Day	45% 10% 15% 21% 9%	2619
	21st to end	Day	51% 9% 14% 22% 5%	2602
August	1st to 10th	Day	53% 9% 14% 20% 3	2432
	11th to 20th	Day	49% 10% 16% 16% 8%	2303
	21st to end	Day	50% 8% 13% 21% 7%	2496
September	1st to 10th	Day	49% 9% 13% 20% 8% 1	2160
	11th to 20th	Day	52% 8% 15% 19% 5%	2150
	21st to end	Day	55% 8% 11% 21% 6%	1886
October	1st to 10th	Day	57% 5% 12% 17% 8% 1	1800
	11th to 20th	Day	72% 6% 10% 9% 3 1	1800
	21st to end	Day	73% 5% 9% 9% 4	1859
November	1st to 10th	Day	71% 6% 11% 8% 4	1486
	11th to 20th	Day	77% 5% 8% 8% 2	1520
	21st to end	Day	84% 5% 5% 5% 2	1520
December	1st to 10th	Day	77% 5% 8% 8% 2	1520
	11th to 20th	Day	74% 5% 5% 13% 3	1719
	21st to end	Day	80% 4 6% 9% 1	2431
January	1st to 10th	Night	77% 5% 10% 6% 1	4748
	11th to 20th	Night	72% 6% 6% 11% 5%	4714
	21st to end	Night	75% 5% 6% 9% 5% 1	4748
February	1st to 10th	Night	64% 7% 8% 13% 8%	2470
	11th to 20th	Night	67% 5% 8% 14% 6%	2405
	21st to end	Night	66% 4 8% 14% 7% 1	2023
March	1st to 10th	Night	62% 5% 9% 13% 11% 1	2180
	11th to 20th	Night	66% 4 7% 12% 8% 2	2090
	21st to end	Night	53% 4 9% 17% 14% 3	2214
April	1st to 10th	Night	60% 4 8% 14% 13% 1	1800
	11th to 20th	Night	52% 6% 10% 20% 11% 1	1696
	21st to end	Night	52% 5% 7% 18% 16% 2	1602
May	1st to 10th	Night	50% 5% 11% 18% 13% 3	1440
	11th to 20th	Night	49% 7% 10% 20% 14% 1	1416
	21st to end	Night	47% 6% 10% 20% 15% 2	1551
June	1st to 10th	Night	53% 7% 9% 19% 10% 1	1260
	11th to 20th	Night	45% 6% 10% 21% 14% 4	1260
	21st to end	Night	42% 8% 13% 24% 11% 1	1260
July	1st to 10th	Night	42% 10% 13% 26% 9%	1225
	11th to 20th	Night	40% 7% 18% 23% 12%	1218
	21st to end	Night	46% 10% 16% 23% 6%	1473
August	1st to 10th	Night	46% 7% 18% 24% 5%	1479
	11th to 20th	Night	43% 8% 18% 23% 7% 1	1598
	21st to end	Night	48% 9% 16% 21% 6%	1841
September	1st to 10th	Night	46% 8% 15% 20% 10% 1	1800
	11th to 20th	Night	48% 8% 17% 20% 7%	1808
	21st to end	Night	50% 7% 14% 23% 6%	2074
October	1st to 10th	Night	54% 7% 13% 17% 9% 1	2160
	11th to 20th	Night	69% 6% 10% 13% 2	2160
	21st to end	Night	68% 6% 10% 11% 4 1	2493
November	1st to 10th	Night	66% 7% 13% 12% 2	2592
	11th to 20th	Night	72% 6% 9% 9% 4	2660
	21st to end	Night	79% 5% 7% 7% 1	2660
December	1st to 10th	Night	79% 5% 8% 7% 2	2660
	11th to 20th	Night	76% 4 6% 10% 3	3472
	21st to end	Night	80% 4 4 9% 3	5236

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% 24% 42% 9% 4 1	180
	11th to 20th	Day	17% 18% 39% 20% 5% 1	180
	21st to end	Day	19% 12% 38% 24% 7% 1	236
February	1st to 10th	Day	21% 26% 35% 14% 3	270
	11th to 20th	Day	19% 25% 39% 14% 3	270
	21st to end	Day	24% 24% 38% 12% 2	241
March	1st to 10th	Day	21% 19% 40% 15% 5%	460
	11th to 20th	Day	23% 19% 35% 17% 5%	460
	21st to end	Day	24% 21% 34% 14% 5% 1	490
April	1st to 10th	Day	27% 19% 29% 17% 7% 1	420
	11th to 20th	Day	28% 17% 30% 17% 7% 1	412
	21st to end	Day	28% 19% 30% 17% 5% 1	420
May	1st to 10th	Day	25% 16% 33% 19% 7% 1	423
	11th to 20th	Day	28% 16% 30% 16% 6% 3	447
	21st to end	Day	23% 18% 32% 22% 5% 1	485
June	1st to 10th	Day	24% 15% 34% 20% 6%	625
	11th to 20th	Day	23% 15% 32% 21% 7% 2	630
	21st to end	Day	20% 12% 31% 27% 9% 2	630
July	1st to 10th	Day	18% 13% 36% 23% 9% 1	621
	11th to 20th	Day	18% 13% 35% 23% 10% 1	618
	21st to end	Day	18% 11% 31% 26% 11% 2	499
August	1st to 10th	Day	21% 9% 29% 26% 11% 3	446
	11th to 20th	Day	21% 6% 27% 27% 13% 6%	439
	21st to end	Day	22% 13% 29% 20% 11% 6%	495
September	1st to 10th	Day	21% 13% 35% 18% 9% 3	450
	11th to 20th	Day	24% 9% 34% 23% 8% 1	450
	21st to end	Day	28% 14% 27% 19% 10% 2	450
October	1st to 10th	Day	29% 15% 27% 18% 8% 2	450
	11th to 20th	Day	40% 18% 28% 10% 3 1	450
	21st to end	Day	35% 17% 31% 14% 3	426
November	1st to 10th	Day	34% 26% 31% 8% 1	180
	11th to 20th	Day	28% 22% 33% 16% 2 1	180
	21st to end	Day	41% 23% 28% 5% 2 1	180
December	1st to 10th	Day	26% 17% 33% 16% 7% 1	180
	11th to 20th	Day	23% 17% 46% 10% 2 2	180
	21st to end	Day	32% 15% 33% 13% 5% 2	198
January	1st to 10th	Night	27% 12% 36% 19% 5%	950
	11th to 20th	Night	25% 15% 34% 21% 5%	917
	21st to end	Night	17% 12% 33% 27% 11% 1	836
February	1st to 10th	Night	17% 18% 36% 23% 6%	760
	11th to 20th	Night	22% 13% 34% 25% 5%	743
	21st to end	Night	20% 20% 36% 19% 5%	628
March	1st to 10th	Night	21% 20% 31% 23% 5% 1	760
	11th to 20th	Night	27% 19% 29% 21% 4 1	760
	21st to end	Night	22% 13% 37% 22% 5% 1	821
April	1st to 10th	Night	28% 15% 30% 21% 6%	720
	11th to 20th	Night	24% 17% 27% 24% 8%	632
	21st to end	Night	24% 11% 33% 25% 6% 1	522
May	1st to 10th	Night	23% 11% 31% 25% 9%	360
	11th to 20th	Night	24% 9% 29% 29% 7% 2	354
	21st to end	Night	23% 11% 33% 26% 7%	389
June	1st to 10th	Night	23% 9% 34% 24% 9%	360
	11th to 20th	Night	21% 9% 32% 30% 8%	360
	21st to end	Night	17% 8% 28% 34% 13%	360
July	1st to 10th	Night	18% 9% 31% 33% 8% 1	350
	11th to 20th	Night	16% 8% 26% 37% 12%	348
	21st to end	Night	15% 6% 28% 37% 13% 1	394
August	1st to 10th	Night	20% 5% 26% 31% 16% 2	415
	11th to 20th	Night	17% 6% 26% 31% 19% 1	534
	21st to end	Night	23% 9% 26% 26% 14% 3	653
September	1st to 10th	Night	23% 8% 30% 26% 12% 2	720
	11th to 20th	Night	26% 11% 27% 25% 11% 1	720
	21st to end	Night	28% 9% 26% 25% 11% 1	720
October	1st to 10th	Night	28% 12% 28% 23% 8% 1	720
	11th to 20th	Night	38% 13% 27% 16% 6% 1	720
	21st to end	Night	38% 10% 31% 16% 4 1	792
November	1st to 10th	Night	30% 15% 35% 15% 5% 1	740
	11th to 20th	Night	31% 18% 30% 16% 5%	760
	21st to end	Night	35% 16% 31% 15% 3	760
December	1st to 10th	Night	31% 16% 30% 18% 5% 1	760
	11th to 20th	Night	27% 17% 31% 18% 6% 2	897
	21st to end	Night	30% 18% 26% 19% 6% 1	1045

Page generated at 2024-03-24 23:37:04. Version ac07

Copyright © 2024 Attilla Danko.