Marieville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Marieville clear sky chart from 2005-11-06 to 2024-01-22.

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% 9% 4 7% 6% 3 5% 5% 5% 7% 32%	74835
	Night	19% 11% 4 7% 6% 3 4 4 5% 6% 31%	75095
Transparency	Day	51% 7% 13% 19% 9% 1	74540
	Night	54% 7% 11% 18% 9% 1	74924
Seeing	Day	22% 12% 28% 24% 12% 3	13520
	Night	24% 10% 28% 28% 9% 1	22602

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	21% 19% 6% 10% 6% 3 4 4 3 4 19%	1517
	11th to 20th	Day	20% 17% 7% 9% 6% 3 5% 4 4 5% 21%	1520
	21st to end	Day	12% 14% 5% 9% 7% 4 6% 5% 5% 6% 27%	1592
February	1st to 10th	Day	17% 17% 5% 10% 8% 4 5% 4 3 6% 21%	1556
	11th to 20th	Day	15% 14% 7% 10% 6% 3 5% 4 5% 6% 25%	1692
	21st to end	Day	18% 15% 6% 7% 7% 3 5% 5% 4 6% 25%	1480
March	1st to 10th	Day	16% 12% 5% 8% 7% 4 6% 5% 4 5% 28%	1797
	11th to 20th	Day	18% 11% 4 7% 6% 3 5% 5% 4 7% 31%	1850
	21st to end	Day	20% 10% 4 6% 6% 3 5% 5% 4 6% 33%	2376
April	1st to 10th	Day	23% 10% 4 6% 7% 4 4 4 4 5% 29%	2160
	11th to 20th	Day	22% 8% 3 5% 4 3 4 4 4 6% 37%	2134
	21st to end	Day	23% 9% 3 6% 5% 3 5% 4 4 6% 31%	2326
May	1st to 10th	Day	20% 9% 3 7% 5% 3 4 4 4 6% 35%	2448
	11th to 20th	Day	18% 7% 3 6% 5% 3 5% 4 5% 7% 36%	2478
	21st to end	Day	18% 5% 3 6% 6% 3 6% 5% 6% 8% 34%	2725
June	1st to 10th	Day	22% 7% 3 6% 5% 3 5% 5% 6% 8% 30%	2520
	11th to 20th	Day	16% 6% 3 5% 4 3 5% 5% 6% 9% 38%	2520
	21st to end	Day	20% 8% 4 6% 5% 3 5% 5% 6% 7% 31%	2520
July	1st to 10th	Day	13% 6% 3 5% 5% 4 5% 5% 7% 9% 40%	2520
	11th to 20th	Day	13% 6% 2 6% 6% 4 6% 6% 7% 10% 36%	2520
	21st to end	Day	14% 6% 2 6% 5% 3 5% 6% 7% 9% 37%	2744
August	1st to 10th	Day	13% 6% 3 6% 6% 4 5% 7% 6% 9% 36%	2506
	11th to 20th	Day	11% 6% 2 5% 6% 3 6% 5% 6% 9% 41%	2286
	21st to end	Day	14% 5% 2 5% 5% 3 5% 4 6% 8% 41%	2376
September	1st to 10th	Day	13% 5% 3 5% 4 4 5% 5% 6% 7% 42%	2160
	11th to 20th	Day	16% 6% 2 4 4 3 3 3 5% 7% 48%	2063
	21st to end	Day	16% 7% 3 5% 6% 2 4 5% 6% 8% 39%	1980
October	1st to 10th	Day	21% 8% 2 6% 5% 3 6% 5% 5% 7% 31%	1890
	11th to 20th	Day	20% 9% 3 6% 7% 4 5% 5% 5% 7% 28%	1738
	21st to end	Day	27% 9% 3 6% 5% 4 4 3 4 5% 29%	1782
November	1st to 10th	Day	19% 10% 3 6% 6% 4 4 4 4 7% 33%	1671
	11th to 20th	Day	18% 12% 4 8% 6% 4 4 5% 5% 7% 26%	1670
	21st to end	Day	24% 12% 4 8% 6% 4 4 5% 5% 5% 24%	1520
December	1st to 10th	Day	25% 15% 6% 9% 6% 4 4 4 5% 4 18%	1520
	11th to 20th	Day	23% 14% 4 8% 5% 3 5% 4 5% 5% 24%	1906
	21st to end	Day	28% 15% 5% 10% 6% 3 4 3 4 3 18%	2772
January	1st to 10th	Night	20% 17% 7% 10% 7% 4 4 4 4 4 19%	2649
	11th to 20th	Night	18% 17% 6% 11% 6% 4 5% 4 4 4 21%	2660
	21st to end	Night	15% 13% 6% 8% 9% 4 4 4 4 5% 27%	2798
February	1st to 10th	Night	17% 16% 6% 11% 8% 4 5% 4 4 5% 19%	2403
	11th to 20th	Night	16% 12% 6% 10% 8% 4 5% 5% 4 5% 27%	2152
	21st to end	Night	18% 14% 4 8% 7% 3 4 4 4 5% 30%	1776
March	1st to 10th	Night	17% 14% 5% 8% 7% 3 4 4 4 6% 28%	2150
	11th to 20th	Night	20% 12% 5% 7% 6% 3 4 3 4 5% 30%	2104
	21st to end	Night	19% 11% 4 6% 5% 3 4 4 4 4 36%	1980
April	1st to 10th	Night	25% 9% 4 7% 5% 3 5% 4 4 6% 29%	1800
	11th to 20th	Night	23% 9% 3 6% 5% 2 4 3 4 6% 34%	1775
	21st to end	Night	22% 10% 3 6% 5% 3 4 3 4 6% 34%	1633
May	1st to 10th	Night	21% 9% 4 7% 5% 3 4 3 3 6% 34%	1528
	11th to 20th	Night	19% 9% 3 6% 5% 3 4 4 5% 6% 36%	1415
	21st to end	Night	17% 6% 3 5% 5% 4 4 5% 5% 7% 39%	1550
June	1st to 10th	Night	24% 7% 3 5% 4 3 5% 4 6% 7% 31%	1440
	11th to 20th	Night	18% 4 2 5% 6% 2 4 5% 7% 9% 36%	1440
	21st to end	Night	17% 7% 4 8% 5% 3 5% 5% 6% 7% 34%	1440
July	1st to 10th	Night	12% 5% 3 5% 6% 3 6% 5% 8% 9% 38%	1440
	11th to 20th	Night	10% 5% 2 6% 5% 3 6% 6% 7% 9% 40%	1440
	21st to end	Night	13% 5% 3 6% 6% 4 6% 5% 6% 8% 38%	1574
August	1st to 10th	Night	14% 5% 2 5% 4 3 5% 4 7% 9% 40%	1432
	11th to 20th	Night	13% 6% 3 5% 5% 3 4 6% 6% 8% 40%	1594
	21st to end	Night	13% 7% 2 6% 5% 3 5% 5% 6% 8% 41%	1980
September	1st to 10th	Night	14% 6% 2 5% 5% 3 5% 5% 5% 7% 42%	1800
	11th to 20th	Night	16% 5% 2 4 4 2 4 3 5% 7% 47%	1896
	21st to end	Night	18% 6% 2 5% 5% 3 3 5% 5% 6% 42%	1980
October	1st to 10th	Night	18% 7% 3 6% 5% 2 4 5% 5% 7% 38%	2065
	11th to 20th	Night	22% 8% 4 6% 7% 4 4 4 5% 5% 31%	2220
	21st to end	Night	25% 9% 4 7% 7% 3 4 5% 4 5% 29%	2574
November	1st to 10th	Night	20% 11% 3 6% 5% 3 5% 5% 5% 6% 31%	2407
	11th to 20th	Night	21% 10% 4 8% 5% 3 5% 4 4 5% 30%	2508
	21st to end	Night	23% 13% 5% 7% 6% 3 5% 3 4 5% 26%	2660
December	1st to 10th	Night	24% 17% 7% 9% 6% 3 4 4 4 6% 17%	2660
	11th to 20th	Night	23% 15% 6% 8% 6% 3 4 3 3 4 23%	3288
	21st to end	Night	27% 15% 6% 10% 5% 2 3 3 3 4 21%	4884

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	69% 6% 9% 12% 3	1518
	11th to 20th	Day	66% 6% 9% 12% 7%	1520
	21st to end	Day	58% 7% 12% 17% 6% 1	1592
February	1st to 10th	Day	65% 6% 8% 16% 4 1	1556
	11th to 20th	Day	60% 5% 12% 15% 6% 1	1701
	21st to end	Day	60% 6% 11% 14% 8% 1	1480
March	1st to 10th	Day	57% 6% 10% 17% 8% 2	1800
	11th to 20th	Day	53% 6% 13% 15% 11% 2	1850
	21st to end	Day	53% 5% 9% 20% 10% 2	2376
April	1st to 10th	Day	57% 6% 9% 18% 9% 1	2160
	11th to 20th	Day	48% 6% 10% 22% 13% 1	2134
	21st to end	Day	53% 6% 11% 17% 10% 3	2326
May	1st to 10th	Day	49% 5% 10% 20% 14% 2	2448
	11th to 20th	Day	46% 7% 12% 19% 14% 2	2482
	21st to end	Day	47% 8% 13% 18% 12% 2	2725
June	1st to 10th	Day	51% 8% 12% 18% 10% 1	2520
	11th to 20th	Day	43% 7% 12% 23% 13% 2	2520
	21st to end	Day	51% 8% 13% 19% 9% 1	2520
July	1st to 10th	Day	39% 9% 14% 27% 11% 1	2450
	11th to 20th	Day	40% 9% 15% 28% 7%	2445
	21st to end	Day	41% 9% 18% 24% 8%	2591
August	1st to 10th	Day	42% 10% 17% 24% 7%	2492
	11th to 20th	Day	38% 9% 19% 23% 11%	2286
	21st to end	Day	39% 8% 16% 25% 11%	2376
September	1st to 10th	Day	39% 9% 14% 26% 11% 1	2160
	11th to 20th	Day	36% 6% 13% 31% 13%	2063
	21st to end	Day	42% 8% 15% 25% 10% 1	1980
October	1st to 10th	Day	51% 8% 13% 19% 9%	1890
	11th to 20th	Day	53% 10% 13% 18% 6%	1738
	21st to end	Day	59% 6% 12% 16% 6% 1	1782
November	1st to 10th	Day	51% 7% 14% 19% 8% 1	1671
	11th to 20th	Day	56% 8% 12% 15% 8%	1670
	21st to end	Day	61% 9% 12% 13% 5%	1520
December	1st to 10th	Day	69% 8% 10% 11% 2	1520
	11th to 20th	Day	62% 7% 11% 14% 6%	1906
	21st to end	Day	71% 5% 12% 8% 4	2772
January	1st to 10th	Night	68% 8% 9% 11% 4	2649
	11th to 20th	Night	66% 7% 9% 11% 6% 1	2660
	21st to end	Night	60% 6% 10% 15% 9% 1	2798
February	1st to 10th	Night	67% 6% 9% 13% 5% 1	2403
	11th to 20th	Night	60% 6% 10% 16% 7%	2154
	21st to end	Night	58% 5% 9% 15% 12% 1	1776
March	1st to 10th	Night	58% 5% 9% 17% 9% 2	2160
	11th to 20th	Night	57% 5% 9% 15% 11% 2	2105
	21st to end	Night	51% 5% 9% 19% 13% 3	1980
April	1st to 10th	Night	56% 5% 9% 17% 11% 2	1800
	11th to 20th	Night	52% 5% 8% 20% 13% 2	1775
	21st to end	Night	52% 6% 8% 19% 12% 3	1633
May	1st to 10th	Night	52% 5% 7% 17% 14% 5%	1528
	11th to 20th	Night	48% 5% 10% 18% 17% 3	1416
	21st to end	Night	44% 8% 11% 20% 15% 2	1551
June	1st to 10th	Night	51% 7% 10% 21% 10% 1	1440
	11th to 20th	Night	44% 7% 13% 20% 13% 3	1440
	21st to end	Night	47% 9% 13% 19% 12%	1440
July	1st to 10th	Night	38% 10% 13% 24% 14% 1	1400
	11th to 20th	Night	37% 9% 16% 27% 12%	1392
	21st to end	Night	40% 9% 16% 25% 9% 1	1486
August	1st to 10th	Night	39% 9% 17% 25% 10%	1422
	11th to 20th	Night	39% 9% 17% 23% 12%	1594
	21st to end	Night	40% 9% 14% 25% 12% 1	1980
September	1st to 10th	Night	40% 8% 12% 24% 14% 1	1800
	11th to 20th	Night	37% 5% 16% 30% 12% 1	1896
	21st to end	Night	42% 8% 10% 24% 14% 1	1980
October	1st to 10th	Night	45% 7% 12% 23% 12% 1	2065
	11th to 20th	Night	53% 7% 11% 22% 6%	2220
	21st to end	Night	58% 7% 11% 15% 8% 1	2574
November	1st to 10th	Night	53% 6% 12% 21% 7% 1	2407
	11th to 20th	Night	55% 7% 12% 16% 9% 1	2508
	21st to end	Night	61% 7% 11% 15% 5%	2660
December	1st to 10th	Night	70% 6% 11% 10% 3	2660
	11th to 20th	Night	65% 5% 9% 14% 5%	3288
	21st to end	Night	68% 6% 10% 13% 3	4884

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	31% 13% 28% 18% 8% 2	180
	11th to 20th	Day	28% 18% 32% 17% 5% 1	180
	21st to end	Day	19% 16% 33% 21% 8% 2	178
February	1st to 10th	Day	33% 22% 31% 13% 1	212
	11th to 20th	Day	26% 13% 36% 21% 4 1	360
	21st to end	Day	26% 15% 28% 28% 3	346
March	1st to 10th	Day	25% 12% 30% 27% 6%	420
	11th to 20th	Day	24% 14% 35% 19% 8% 1	420
	21st to end	Day	28% 13% 27% 21% 9% 1	462
April	1st to 10th	Day	31% 13% 28% 19% 8% 1	420
	11th to 20th	Day	29% 18% 23% 17% 10% 4	412
	21st to end	Day	27% 14% 29% 17% 10% 3	420
May	1st to 10th	Day	25% 13% 30% 19% 11% 2	423
	11th to 20th	Day	18% 11% 30% 28% 10% 3	447
	21st to end	Day	19% 10% 34% 23% 12% 2	485
June	1st to 10th	Day	24% 11% 25% 28% 10% 2	450
	11th to 20th	Day	16% 11% 26% 30% 15% 2	450
	21st to end	Day	20% 10% 28% 24% 15% 2	450
July	1st to 10th	Day	12% 7% 26% 33% 18% 4	445
	11th to 20th	Day	14% 7% 28% 31% 14% 5%	444
	21st to end	Day	16% 7% 25% 31% 19% 2	488
August	1st to 10th	Day	14% 5% 24% 30% 22% 5%	446
	11th to 20th	Day	12% 6% 25% 31% 19% 7%	439
	21st to end	Day	15% 9% 24% 25% 17% 10%	495
September	1st to 10th	Day	13% 8% 27% 27% 17% 8%	450
	11th to 20th	Day	16% 9% 21% 26% 17% 11%	450
	21st to end	Day	16% 8% 29% 22% 18% 6%	450
October	1st to 10th	Day	22% 12% 28% 19% 14% 4	450
	11th to 20th	Day	24% 14% 28% 20% 12% 2	419
	21st to end	Day	34% 13% 26% 21% 7%	396
November	1st to 10th	Day	28% 15% 27% 22% 8%	365
	11th to 20th	Day	25% 20% 28% 16% 9% 1	330
	21st to end	Day	32% 14% 29% 18% 5% 1	180
December	1st to 10th	Day	34% 12% 22% 22% 8% 2	180
	11th to 20th	Day	26% 23% 33% 14% 4	180
	21st to end	Day	33% 20% 26% 16% 4 2	198
January	1st to 10th	Night	28% 11% 31% 25% 5%	760
	11th to 20th	Night	26% 13% 34% 21% 6%	760
	21st to end	Night	22% 10% 33% 28% 7% 1	800
February	1st to 10th	Night	26% 9% 35% 25% 5%	720
	11th to 20th	Night	23% 10% 37% 26% 5%	703
	21st to end	Night	24% 12% 31% 29% 4	592
March	1st to 10th	Night	25% 12% 29% 29% 5%	720
	11th to 20th	Night	27% 12% 30% 25% 7%	720
	21st to end	Night	25% 10% 29% 28% 7% 1	792
April	1st to 10th	Night	28% 10% 27% 28% 6%	720
	11th to 20th	Night	26% 14% 27% 25% 7% 1	711
	21st to end	Night	27% 10% 30% 24% 8% 1	553
May	1st to 10th	Night	26% 7% 31% 25% 10% 1	448
	11th to 20th	Night	22% 8% 30% 31% 8% 1	354
	21st to end	Night	18% 8% 31% 33% 9%	389
June	1st to 10th	Night	26% 7% 28% 30% 9% 1	360
	11th to 20th	Night	21% 5% 26% 34% 14%	360
	21st to end	Night	17% 6% 28% 36% 13% 1	360
July	1st to 10th	Night	12% 3 30% 40% 14% 1	350
	11th to 20th	Night	11% 3 21% 47% 17% 1	348
	21st to end	Night	13% 3 22% 46% 15% 1	394
August	1st to 10th	Night	15% 3 18% 46% 18% 1	358
	11th to 20th	Night	14% 5% 21% 35% 24% 2	530
	21st to end	Night	15% 5% 20% 38% 19% 2	792
September	1st to 10th	Night	16% 5% 23% 38% 17% 1	720
	11th to 20th	Night	19% 6% 18% 35% 20% 3	720
	21st to end	Night	20% 6% 28% 29% 14% 3	720
October	1st to 10th	Night	22% 7% 28% 29% 14%	720
	11th to 20th	Night	26% 9% 28% 28% 8% 1	720
	21st to end	Night	29% 11% 31% 24% 5%	792
November	1st to 10th	Night	25% 13% 31% 23% 8% 1	740
	11th to 20th	Night	25% 15% 29% 21% 9% 1	760
	21st to end	Night	30% 14% 29% 20% 6%	760
December	1st to 10th	Night	33% 14% 26% 22% 5%	760
	11th to 20th	Night	29% 14% 30% 19% 6% 1	760
	21st to end	Night	33% 13% 30% 19% 4	836

Page generated at 2024-01-19 09:28:37. Version ac07

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