Barnes City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Barnes City clear sky chart from 2005-11-06 to 2024-01-12.

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	13% 8% 3 6% 5% 3 5% 4 5% 7% 39%	74710
	Night	12% 8% 3 6% 5% 3 4 4 5% 7% 42%	75026
Transparency	Day	44% 5% 13% 23% 13% 2	74419
	Night	42% 5% 12% 24% 14% 2	74838
Seeing	Day	16% 10% 29% 26% 15% 4	14651
	Night	16% 9% 32% 31% 12% 1	24633

By Month

Percentage Cloud Cover SE (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	10% 11% 5% 11% 9% 5% 5% 5% 4 7% 28%	1517
	11th to 20th	Day	12% 13% 6% 10% 9% 3 5% 5% 5% 6% 26%	1565
	21st to end	Day	14% 12% 7% 10% 7% 4 4 5% 4 6% 26%	1782
February	1st to 10th	Day	13% 12% 5% 8% 8% 3 5% 5% 4 7% 30%	1620
	11th to 20th	Day	13% 12% 4 6% 6% 3 5% 5% 5% 8% 34%	1574
	21st to end	Day	15% 9% 5% 9% 6% 3 4 4 4 6% 34%	1471
March	1st to 10th	Day	15% 10% 5% 7% 6% 3 4 4 5% 7% 35%	1930
	11th to 20th	Day	14% 10% 4 8% 6% 3 5% 4 5% 6% 34%	1980
	21st to end	Day	23% 12% 3 6% 5% 3 4 3 5% 6% 28%	2214
April	1st to 10th	Day	17% 10% 3 6% 6% 3 4 4 5% 6% 34%	2160
	11th to 20th	Day	17% 9% 3 6% 5% 4 5% 4 4 8% 34%	2134
	21st to end	Day	22% 8% 3 6% 5% 3 4 4 5% 7% 33%	2204
May	1st to 10th	Day	18% 8% 4 7% 6% 4 5% 5% 6% 6% 32%	2362
	11th to 20th	Day	18% 8% 2 6% 5% 3 5% 4 6% 6% 36%	2479
	21st to end	Day	15% 6% 3 6% 6% 4 5% 5% 6% 7% 37%	2725
June	1st to 10th	Day	10% 5% 2 5% 5% 3 5% 6% 7% 9% 44%	2520
	11th to 20th	Day	9% 4 2 5% 5% 3 5% 5% 5% 9% 48%	2520
	21st to end	Day	11% 5% 3 6% 5% 4 5% 5% 6% 9% 39%	2520
July	1st to 10th	Day	8% 4 2 5% 5% 2 4 5% 7% 9% 49%	2520
	11th to 20th	Day	8% 3 2 5% 5% 3 5% 5% 6% 9% 48%	2520
	21st to end	Day	6% 5% 1 5% 4 3 5% 6% 8% 11% 47%	2598
August	1st to 10th	Day	7% 5% 2 5% 6% 4 6% 6% 8% 10% 41%	2328
	11th to 20th	Day	8% 6% 3 5% 6% 3 5% 5% 6% 8% 45%	2293
	21st to end	Day	9% 4 2 6% 5% 3 5% 4 6% 7% 50%	2376
September	1st to 10th	Day	14% 5% 2 5% 3 2 3 3 5% 6% 51%	2160
	11th to 20th	Day	10% 4 2 4 4 3 4 4 5% 9% 51%	2160
	21st to end	Day	11% 5% 3 4 4 3 5% 4 5% 7% 49%	1884
October	1st to 10th	Day	15% 6% 2 6% 5% 3 4 3 4 6% 46%	1800
	11th to 20th	Day	17% 8% 2 6% 4 3 4 3 4 6% 44%	1800
	21st to end	Day	15% 9% 3 6% 5% 3 3 4 4 6% 41%	1980
November	1st to 10th	Day	10% 8% 2 5% 5% 3 5% 4 6% 8% 46%	1700
	11th to 20th	Day	15% 9% 3 7% 4 3 4 4 5% 8% 38%	1573
	21st to end	Day	16% 10% 4 6% 5% 2 4 4 4 8% 38%	1520
December	1st to 10th	Day	13% 12% 5% 8% 6% 3 4 4 4 6% 34%	1520
	11th to 20th	Day	13% 9% 5% 8% 6% 3 5% 5% 5% 6% 34%	1918
	21st to end	Day	23% 17% 9% 11% 6% 3 4 4 3 4 17%	2783
January	1st to 10th	Night	9% 10% 5% 8% 6% 4 5% 4 5% 7% 38%	2648
	11th to 20th	Night	11% 12% 7% 10% 8% 4 5% 5% 4 6% 29%	2419
	21st to end	Night	13% 12% 5% 8% 6% 3 4 4 5% 7% 33%	2574
February	1st to 10th	Night	14% 12% 5% 8% 6% 3 5% 4 3 5% 34%	2340
	11th to 20th	Night	12% 9% 3 7% 5% 3 5% 4 5% 7% 40%	2273
	21st to end	Night	14% 10% 3 8% 5% 3 5% 3 4 6% 40%	1783
March	1st to 10th	Night	15% 9% 3 6% 4 3 3 3 4 5% 44%	2045
	11th to 20th	Night	14% 8% 4 6% 6% 2 4 3 5% 6% 39%	1980
	21st to end	Night	20% 10% 5% 8% 6% 4 5% 4 4 5% 28%	2142
April	1st to 10th	Night	14% 8% 4 7% 4 3 4 4 5% 6% 42%	1800
	11th to 20th	Night	15% 9% 3 5% 5% 4 4 5% 4 5% 40%	1775
	21st to end	Night	18% 7% 3 4 5% 2 4 4 5% 7% 40%	1751
May	1st to 10th	Night	15% 5% 2 6% 5% 4 5% 4 6% 9% 39%	1598
	11th to 20th	Night	17% 7% 3 5% 4 3 4 4 5% 7% 42%	1416
	21st to end	Night	12% 5% 3 5% 5% 4 4 5% 5% 9% 42%	1551
June	1st to 10th	Night	5% 5% 2 4 4 3 5% 5% 7% 9% 50%	1440
	11th to 20th	Night	7% 4 2 5% 4 3 4 5% 6% 12% 48%	1440
	21st to end	Night	9% 4 2 5% 4 3 6% 5% 7% 8% 47%	1440
July	1st to 10th	Night	5% 3 1 3 5% 3 5% 6% 6% 10% 54%	1440
	11th to 20th	Night	5% 2 1 3 3 2 4 4 5% 9% 61%	1440
	21st to end	Night	7% 3 2 4 4 3 3 5% 7% 10% 53%	1717
August	1st to 10th	Night	5% 4 2 5% 5% 2 5% 5% 6% 10% 51%	1611
	11th to 20th	Night	6% 4 2 4 4 2 4 5% 5% 7% 56%	1608
	21st to end	Night	8% 4 1 4 3 2 4 4 5% 8% 56%	1980
September	1st to 10th	Night	10% 5% 2 4 4 3 3 4 5% 6% 56%	1800
	11th to 20th	Night	11% 5% 1 4 4 3 4 3 4 8% 53%	1800
	21st to end	Night	9% 5% 2 4 4 3 4 3 4 8% 56%	2052
October	1st to 10th	Night	13% 6% 2 4 3 2 3 4 4 6% 52%	2160
	11th to 20th	Night	14% 6% 3 5% 4 2 4 4 4 5% 49%	2160
	21st to end	Night	17% 8% 3 5% 6% 3 3 3 4 6% 43%	2376
November	1st to 10th	Night	10% 6% 2 4 3 2 3 4 5% 7% 54%	2378
	11th to 20th	Night	13% 8% 3 6% 4 3 4 4 5% 7% 42%	2606
	21st to end	Night	17% 7% 4 6% 4 3 4 4 4 5% 41%	2660
December	1st to 10th	Night	12% 11% 5% 8% 6% 3 5% 4 5% 6% 37%	2660
	11th to 20th	Night	12% 9% 4 8% 7% 3 4 4 4 6% 38%	3279
	21st to end	Night	20% 16% 7% 10% 6% 3 4 4 4 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	57% 4 12% 16% 11% 1	1518
	11th to 20th	Day	60% 3 12% 18% 6%	1565
	21st to end	Day	59% 5% 13% 15% 7% 1	1782
February	1st to 10th	Day	55% 4 15% 18% 8% 1	1620
	11th to 20th	Day	49% 5% 13% 22% 9% 2	1583
	21st to end	Day	52% 4 13% 21% 9% 2	1471
March	1st to 10th	Day	49% 5% 15% 20% 9% 1	1930
	11th to 20th	Day	50% 5% 13% 20% 11% 2	1980
	21st to end	Day	58% 4 12% 18% 7% 2	2214
April	1st to 10th	Day	50% 4 13% 24% 9%	2160
	11th to 20th	Day	49% 5% 11% 23% 11% 1	2134
	21st to end	Day	51% 5% 11% 20% 12% 1	2204
May	1st to 10th	Day	51% 6% 13% 20% 9% 1	2362
	11th to 20th	Day	48% 6% 12% 22% 12% 1	2483
	21st to end	Day	46% 7% 12% 21% 12% 2	2725
June	1st to 10th	Day	36% 7% 17% 25% 14% 2	2520
	11th to 20th	Day	33% 6% 12% 24% 21% 4	2520
	21st to end	Day	40% 8% 14% 22% 15% 2	2520
July	1st to 10th	Day	30% 6% 16% 31% 14% 3	2451
	11th to 20th	Day	33% 7% 15% 27% 15% 3	2445
	21st to end	Day	29% 8% 19% 27% 16% 1	2454
August	1st to 10th	Day	35% 9% 17% 27% 12% 1	2314
	11th to 20th	Day	35% 6% 13% 28% 16% 2	2293
	21st to end	Day	33% 6% 11% 27% 20% 4	2376
September	1st to 10th	Day	35% 5% 12% 23% 21% 4	2160
	11th to 20th	Day	30% 5% 13% 30% 20% 2	2160
	21st to end	Day	34% 4 10% 33% 17% 1	1884
October	1st to 10th	Day	40% 3 10% 25% 20% 1	1800
	11th to 20th	Day	43% 3 9% 24% 19% 2	1800
	21st to end	Day	45% 4 12% 23% 14% 2	1980
November	1st to 10th	Day	37% 4 14% 25% 16% 3	1700
	11th to 20th	Day	46% 4 13% 22% 15% 1	1573
	21st to end	Day	46% 4 15% 24% 10% 1	1520
December	1st to 10th	Day	52% 4 14% 21% 8% 1	1520
	11th to 20th	Day	51% 4 16% 20% 10% 1	1915
	21st to end	Day	72% 3 8% 12% 4 1	2783
January	1st to 10th	Night	46% 4 13% 21% 15% 1	2648
	11th to 20th	Night	57% 5% 15% 16% 8%	2419
	21st to end	Night	52% 4 14% 19% 10% 1	2574
February	1st to 10th	Night	53% 3 11% 21% 11% 1	2340
	11th to 20th	Night	45% 4 11% 26% 12% 2	2274
	21st to end	Night	48% 3 12% 21% 14% 2	1783
March	1st to 10th	Night	44% 4 12% 28% 12% 1	2045
	11th to 20th	Night	46% 4 13% 22% 13% 2	1980
	21st to end	Night	59% 4 12% 15% 9% 1	2142
April	1st to 10th	Night	44% 4 10% 26% 14% 2	1800
	11th to 20th	Night	46% 5% 9% 22% 15% 3	1775
	21st to end	Night	43% 5% 12% 23% 13% 3	1751
May	1st to 10th	Night	42% 6% 14% 23% 14% 1	1598
	11th to 20th	Night	41% 5% 16% 23% 13% 1	1417
	21st to end	Night	38% 8% 12% 23% 16% 3	1552
June	1st to 10th	Night	29% 7% 17% 28% 16% 3	1440
	11th to 20th	Night	28% 7% 15% 24% 22% 5%	1440
	21st to end	Night	32% 9% 13% 24% 17% 4	1440
July	1st to 10th	Night	24% 8% 17% 32% 16% 4	1400
	11th to 20th	Night	21% 6% 18% 34% 17% 3	1392
	21st to end	Night	25% 5% 16% 31% 20% 2	1622
August	1st to 10th	Night	28% 8% 17% 31% 13% 3	1601
	11th to 20th	Night	27% 7% 12% 34% 18% 2	1608
	21st to end	Night	26% 6% 11% 28% 23% 7%	1980
September	1st to 10th	Night	30% 5% 9% 27% 26% 3	1800
	11th to 20th	Night	31% 4 9% 33% 19% 3	1800
	21st to end	Night	29% 4 9% 32% 22% 3	2052
October	1st to 10th	Night	34% 5% 9% 26% 23% 3	2160
	11th to 20th	Night	38% 4 11% 24% 19% 5%	2160
	21st to end	Night	44% 4 12% 22% 17% 2	2376
November	1st to 10th	Night	30% 4 16% 27% 19% 4	2378
	11th to 20th	Night	42% 4 12% 26% 14% 2	2606
	21st to end	Night	46% 3 12% 26% 12% 1	2660
December	1st to 10th	Night	49% 4 13% 24% 10% 1	2660
	11th to 20th	Night	48% 4 12% 26% 9% 1	3281
	21st to end	Night	67% 4 8% 14% 6% 1	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	21% 13% 33% 21% 10% 1	270
	11th to 20th	Day	25% 11% 42% 19% 4	243
	21st to end	Day	19% 13% 40% 24% 4	264
February	1st to 10th	Day	22% 18% 38% 19% 3	240
	11th to 20th	Day	22% 16% 36% 18% 8%	240
	21st to end	Day	26% 13% 44% 14% 4	198
March	1st to 10th	Day	18% 19% 42% 17% 4	240
	11th to 20th	Day	20% 15% 36% 19% 8% 1	240
	21st to end	Day	36% 17% 28% 16% 3 1	300
April	1st to 10th	Day	25% 15% 32% 20% 7%	420
	11th to 20th	Day	21% 16% 30% 23% 9% 1	412
	21st to end	Day	24% 14% 33% 20% 9% 1	464
May	1st to 10th	Day	20% 12% 36% 22% 7% 2	603
	11th to 20th	Day	22% 12% 27% 25% 12% 2	625
	21st to end	Day	17% 9% 28% 28% 14% 4	679
June	1st to 10th	Day	8% 4 26% 31% 23% 7%	630
	11th to 20th	Day	10% 5% 27% 33% 20% 4	630
	21st to end	Day	11% 7% 30% 31% 16% 4	630
July	1st to 10th	Day	8% 3 18% 30% 27% 14%	621
	11th to 20th	Day	8% 4 25% 33% 24% 8%	618
	21st to end	Day	7% 3 22% 37% 27% 4	684
August	1st to 10th	Day	7% 3 22% 34% 28% 6%	626
	11th to 20th	Day	10% 4 19% 35% 24% 7%	607
	21st to end	Day	9% 3 18% 35% 27% 7%	495
September	1st to 10th	Day	16% 6% 19% 28% 22% 8%	450
	11th to 20th	Day	9% 4 21% 38% 21% 7%	450
	21st to end	Day	14% 10% 30% 22% 20% 5%	288
October	1st to 10th	Day	21% 9% 26% 26% 14% 4	270
	11th to 20th	Day	20% 22% 34% 17% 6% 1	270
	21st to end	Day	22% 14% 35% 20% 8% 2	297
November	1st to 10th	Day	14% 10% 44% 19% 10% 2	270
	11th to 20th	Day	18% 20% 35% 19% 7% 2	270
	21st to end	Day	23% 13% 37% 23% 4	270
December	1st to 10th	Day	15% 13% 40% 21% 10% 2	270
	11th to 20th	Day	14% 17% 35% 25% 8% 1	270
	21st to end	Day	29% 16% 37% 14% 3	297
January	1st to 10th	Night	13% 13% 40% 25% 8%	950
	11th to 20th	Night	18% 12% 36% 27% 7%	908
	21st to end	Night	19% 12% 37% 27% 5%	990
February	1st to 10th	Night	21% 9% 40% 24% 5%	900
	11th to 20th	Night	17% 12% 38% 28% 4	879
	21st to end	Night	20% 14% 39% 21% 5% 1	599
March	1st to 10th	Night	19% 12% 39% 23% 6% 1	605
	11th to 20th	Night	18% 10% 35% 28% 8% 1	540
	21st to end	Night	23% 11% 38% 21% 6% 1	594
April	1st to 10th	Night	19% 13% 41% 25% 3	540
	11th to 20th	Night	21% 13% 34% 26% 7%	533
	21st to end	Night	22% 8% 37% 25% 9% 1	540
May	1st to 10th	Night	19% 6% 37% 30% 7% 1	540
	11th to 20th	Night	18% 10% 29% 31% 11%	531
	21st to end	Night	14% 6% 30% 33% 17%	584
June	1st to 10th	Night	8% 4 23% 46% 18% 1	540
	11th to 20th	Night	9% 4 24% 47% 16% 1	540
	21st to end	Night	9% 5% 28% 41% 16% 1	540
July	1st to 10th	Night	6% 1 13% 43% 34% 3	525
	11th to 20th	Night	6% 2 20% 43% 28% 2	522
	21st to end	Night	7% 2 17% 48% 24% 2	591
August	1st to 10th	Night	6% 1 16% 48% 26% 2	537
	11th to 20th	Night	7% 2 15% 44% 29% 3	534
	21st to end	Night	9% 2 15% 42% 29% 3	594
September	1st to 10th	Night	11% 3 21% 37% 23% 4	540
	11th to 20th	Night	13% 2 20% 38% 24% 3	540
	21st to end	Night	11% 6% 29% 34% 18% 2	634
October	1st to 10th	Night	16% 6% 29% 31% 16% 2	720
	11th to 20th	Night	16% 12% 34% 31% 8%	720
	21st to end	Night	20% 11% 34% 26% 8%	792
November	1st to 10th	Night	14% 9% 39% 29% 9% 1	740
	11th to 20th	Night	17% 15% 39% 23% 7%	896
	21st to end	Night	20% 10% 37% 25% 7%	950
December	1st to 10th	Night	17% 12% 38% 27% 5% 1	950
	11th to 20th	Night	21% 10% 33% 29% 7% 1	950
	21st to end	Night	24% 13% 34% 24% 4	1045

Page generated at 2024-01-09 06:14:41. Version ac07

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