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 2024-11-05.

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 8% 5% 4 4 4 6% 7% 39%	101458
	Night	12% 9% 3 7% 4 4 4 3 5% 6% 42%	97676
Transparency	Day	43% 5% 13% 24% 14% 2	105095
	Night	42% 5% 12% 24% 16% 2	102180
Seeing	Day	16% 10% 30% 26% 15% 4	15835
	Night	16% 9% 32% 31% 12% 1	25662

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	9% 11% 5% 21% 8% 7% 6% 4 4 6% 21%	2527
	11th to 20th	Day	10% 12% 5% 12% 8% 6% 7% 4 6% 6% 24%	2731
	21st to end	Day	14% 17% 7% 16% 7% 5% 4 3 4 5% 19%	3135
February	1st to 10th	Day	12% 13% 5% 9% 6% 4 4 4 5% 7% 30%	1710
	11th to 20th	Day	12% 12% 4 7% 5% 4 4 4 5% 8% 35%	1664
	21st to end	Day	15% 9% 5% 10% 5% 4 4 3 4 6% 36%	1560
March	1st to 10th	Day	17% 11% 4 7% 4 3 3 2 4 5% 40%	3361
	11th to 20th	Day	9% 7% 3 7% 5% 4 4 3 5% 6% 46%	3480
	21st to end	Day	24% 14% 4 9% 4 4 4 3 5% 6% 23%	3877
April	1st to 10th	Day	17% 11% 3 6% 5% 4 4 3 5% 6% 35%	2280
	11th to 20th	Day	16% 9% 2 7% 5% 5% 5% 4 5% 8% 35%	2254
	21st to end	Day	22% 9% 3 7% 4 4 4 3 6% 7% 33%	2327
May	1st to 10th	Day	18% 7% 3 7% 5% 5% 4 4 6% 7% 34%	4132
	11th to 20th	Day	16% 7% 2 6% 4 4 4 4 6% 6% 40%	4399
	21st to end	Day	14% 6% 2 6% 4 4 4 4 6% 7% 44%	4824
June	1st to 10th	Day	10% 5% 2 6% 5% 4 5% 5% 7% 9% 44%	2660
	11th to 20th	Day	9% 4 2 6% 4 4 4 4 6% 9% 47%	2660
	21st to end	Day	10% 6% 3 7% 6% 5% 5% 4 6% 9% 39%	2660
July	1st to 10th	Day	10% 8% 3 8% 5% 5% 5% 4 7% 10% 35%	4440
	11th to 20th	Day	6% 4 2 5% 4 4 5% 3 6% 8% 54%	4440
	21st to end	Day	6% 4 1 6% 4 5% 6% 6% 9% 11% 41%	4545
August	1st to 10th	Day	6% 5% 2 5% 5% 4 5% 5% 8% 11% 44%	4104
	11th to 20th	Day	10% 7% 3 7% 5% 5% 5% 4 6% 9% 40%	4019
	21st to end	Day	7% 4 2 6% 4 4 4 3 6% 8% 49%	4180
September	1st to 10th	Day	13% 5% 2 5% 3 3 3 2 5% 6% 53%	2280
	11th to 20th	Day	9% 5% 2 5% 4 4 4 3 5% 9% 50%	2280
	21st to end	Day	11% 5% 2 5% 4 4 4 3 5% 7% 49%	1988
October	1st to 10th	Day	14% 6% 2 6% 4 3 4 2 4 6% 49%	1900
	11th to 20th	Day	16% 7% 2 6% 4 4 3 3 4 6% 46%	1900
	21st to end	Day	15% 10% 2 6% 5% 4 3 3 4 6% 42%	2090
November	1st to 10th	Day	10% 8% 2 6% 4 4 4 3 6% 7% 46%	1737
	11th to 20th	Day	15% 10% 2 8% 4 3 4 3 5% 8% 38%	1573
	21st to end	Day	16% 11% 3 6% 4 3 3 3 4 8% 38%	1520
December	1st to 10th	Day	13% 13% 5% 8% 5% 4 4 3 5% 5% 34%	1520
	11th to 20th	Day	13% 9% 4 9% 5% 5% 4 3 5% 6% 34%	1918
	21st to end	Day	22% 17% 8% 12% 5% 4 4 3 4 4 17%	2783
January	1st to 10th	Night	11% 11% 7% 18% 6% 4 4 3 4 5% 27%	4428
	11th to 20th	Night	12% 15% 6% 12% 5% 4 6% 3 8% 6% 23%	4234
	21st to end	Night	16% 16% 6% 12% 5% 4 4 3 4 6% 23%	4532
February	1st to 10th	Night	13% 13% 4 9% 5% 4 4 3 4 6% 35%	2470
	11th to 20th	Night	11% 10% 3 7% 5% 4 4 3 5% 7% 41%	2403
	21st to end	Night	13% 10% 3 8% 4 5% 3 2 4 5% 41%	1892
March	1st to 10th	Night	16% 9% 3 6% 3 4 3 2 4 4 46%	3521
	11th to 20th	Night	11% 7% 2 5% 4 3 3 2 5% 6% 51%	3480
	21st to end	Night	21% 11% 5% 12% 5% 5% 4 3 4 5% 25%	3754
April	1st to 10th	Night	15% 9% 3 7% 4 3 3 4 5% 5% 42%	1900
	11th to 20th	Night	14% 9% 3 6% 4 5% 4 3 5% 5% 41%	1875
	21st to end	Night	18% 8% 2 5% 4 3 4 3 5% 7% 41%	1848
May	1st to 10th	Night	20% 6% 2 6% 4 4 5% 3 5% 7% 37%	2773
	11th to 20th	Night	12% 7% 2 6% 4 4 4 3 5% 6% 46%	2506
	21st to end	Night	9% 6% 2 6% 4 5% 4 4 5% 8% 47%	2743
June	1st to 10th	Night	6% 5% 2 5% 4 4 4 4 7% 9% 49%	1520
	11th to 20th	Night	7% 4 2 5% 4 4 4 4 6% 12% 48%	1520
	21st to end	Night	9% 5% 1 6% 3 5% 5% 4 7% 7% 46%	1520
July	1st to 10th	Night	10% 5% 2 6% 5% 5% 5% 5% 6% 8% 44%	2530
	11th to 20th	Night	4 2 1 3 3 3 4 3 6% 9% 62%	2530
	21st to end	Night	7% 4 2 5% 4 4 4 4 7% 9% 51%	3001
August	1st to 10th	Night	4 4 2 5% 4 3 4 3 5% 9% 56%	2836
	11th to 20th	Night	8% 5% 2 4 3 3 4 3 5% 6% 57%	2819
	21st to end	Night	7% 4 1 6% 3 4 4 4 5% 8% 53%	3476
September	1st to 10th	Night	9% 5% 2 4 3 3 3 2 5% 6% 58%	1900
	11th to 20th	Night	10% 5% 1 5% 3 4 3 2 4 7% 53%	1900
	21st to end	Night	8% 5% 1 5% 3 4 3 3 4 8% 55%	2167
October	1st to 10th	Night	13% 6% 2 5% 3 3 3 3 4 6% 53%	2280
	11th to 20th	Night	13% 6% 3 6% 3 3 4 3 4 5% 51%	2280
	21st to end	Night	16% 8% 3 6% 5% 4 3 3 4 5% 43%	2508
November	1st to 10th	Night	10% 6% 2 4 3 3 3 3 5% 6% 54%	2441
	11th to 20th	Night	12% 9% 3 6% 4 4 4 3 5% 7% 42%	2606
	21st to end	Night	17% 8% 3 7% 4 4 3 3 4 5% 41%	2660
December	1st to 10th	Night	12% 12% 4 9% 5% 4 4 3 5% 5% 37%	2660
	11th to 20th	Night	12% 10% 4 9% 6% 4 4 4 4 6% 38%	3279
	21st to end	Night	20% 17% 6% 11% 5% 4 4 3 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	65% 3 11% 13% 7%	2528
	11th to 20th	Day	61% 3 10% 20% 6%	2731
	21st to end	Day	70% 4 10% 12% 4	3135
February	1st to 10th	Day	54% 4 14% 19% 9% 1	1710
	11th to 20th	Day	47% 5% 13% 23% 10% 2	1673
	21st to end	Day	50% 4 12% 22% 9% 3	1560
March	1st to 10th	Day	48% 4 10% 23% 14% 1	3361
	11th to 20th	Day	38% 5% 12% 25% 18% 2	3480
	21st to end	Day	62% 4 14% 15% 4 1	3877
April	1st to 10th	Day	50% 4 12% 25% 9%	2280
	11th to 20th	Day	48% 5% 11% 22% 11% 2	2254
	21st to end	Day	51% 5% 11% 20% 12% 1	2327
May	1st to 10th	Day	48% 6% 13% 20% 13% 1	4170
	11th to 20th	Day	43% 5% 12% 27% 13%	4403
	21st to end	Day	39% 6% 10% 27% 17% 1	4837
June	1st to 10th	Day	35% 7% 17% 24% 15% 3	2660
	11th to 20th	Day	33% 6% 12% 24% 20% 4	2660
	21st to end	Day	40% 7% 13% 23% 15% 2	2660
July	1st to 10th	Day	43% 6% 13% 26% 9% 2	4371
	11th to 20th	Day	27% 6% 14% 33% 17% 2	4365
	21st to end	Day	31% 11% 19% 22% 16% 1	4402
August	1st to 10th	Day	31% 7% 17% 30% 14% 1	4090
	11th to 20th	Day	40% 6% 13% 25% 15% 1	4058
	21st to end	Day	32% 6% 15% 29% 16% 3	4179
September	1st to 10th	Day	33% 5% 11% 24% 23% 4	2280
	11th to 20th	Day	31% 5% 13% 30% 19% 1	2280
	21st to end	Day	35% 4 10% 32% 18% 2	1988
October	1st to 10th	Day	23% 2 6% 25% 42% 2	3160
	11th to 20th	Day	29% 2 9% 27% 27% 6%	3140
	21st to end	Day	40% 3 10% 28% 16% 3	3428
November	1st to 10th	Day	37% 4 15% 25% 16% 3	1737
	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	61% 3 11% 16% 9%	4428
	11th to 20th	Night	59% 4 12% 14% 10% 1	4234
	21st to end	Night	63% 4 11% 16% 6%	4532
February	1st to 10th	Night	52% 3 11% 23% 11% 1	2470
	11th to 20th	Night	44% 4 11% 27% 12% 2	2404
	21st to end	Night	46% 3 11% 22% 15% 3	1892
March	1st to 10th	Night	43% 4 8% 27% 17% 1	3521
	11th to 20th	Night	35% 4 11% 32% 15% 4	3480
	21st to end	Night	63% 4 17% 10% 5% 1	3754
April	1st to 10th	Night	44% 4 10% 27% 14% 2	1900
	11th to 20th	Night	45% 5% 9% 22% 16% 3	1875
	21st to end	Night	43% 6% 12% 23% 14% 3	1848
May	1st to 10th	Night	45% 6% 10% 19% 17% 2	2800
	11th to 20th	Night	38% 6% 12% 28% 14% 2	2507
	21st to end	Night	35% 6% 11% 26% 21% 2	2751
June	1st to 10th	Night	30% 7% 16% 28% 15% 4	1520
	11th to 20th	Night	28% 7% 14% 25% 22% 4	1520
	21st to end	Night	33% 8% 13% 24% 17% 4	1520
July	1st to 10th	Night	36% 6% 14% 29% 12% 3	2490
	11th to 20th	Night	20% 5% 19% 33% 21% 2	2482
	21st to end	Night	28% 8% 18% 25% 19% 2	2906
August	1st to 10th	Night	25% 6% 17% 33% 17% 2	2826
	11th to 20th	Night	28% 6% 15% 33% 17% 1	2846
	21st to end	Night	28% 6% 14% 29% 17% 6%	3476
September	1st to 10th	Night	28% 5% 8% 28% 27% 3	1900
	11th to 20th	Night	32% 4 9% 33% 19% 3	1900
	21st to end	Night	29% 5% 9% 32% 23% 3	2167
October	1st to 10th	Night	23% 3 6% 24% 40% 4	3800
	11th to 20th	Night	26% 3 9% 24% 30% 8%	3779
	21st to end	Night	44% 3 9% 23% 18% 3	4120
November	1st to 10th	Night	31% 4 15% 27% 19% 4	2441
	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	20% 14% 33% 21% 10% 1	270
	11th to 20th	Day	24% 13% 41% 19% 4	270
	21st to end	Day	18% 13% 40% 24% 5%	297
February	1st to 10th	Day	20% 17% 37% 20% 4	270
	11th to 20th	Day	20% 15% 36% 22% 8%	270
	21st to end	Day	24% 13% 44% 15% 4	225
March	1st to 10th	Day	19% 20% 39% 19% 4	270
	11th to 20th	Day	19% 18% 36% 19% 7% 1	270
	21st to end	Day	34% 18% 30% 15% 3 1	335
April	1st to 10th	Day	26% 15% 33% 19% 7%	460
	11th to 20th	Day	21% 17% 31% 22% 8% 1	452
	21st to end	Day	23% 14% 34% 19% 8% 1	507
May	1st to 10th	Day	20% 13% 37% 22% 7% 2	653
	11th to 20th	Day	21% 12% 27% 25% 12% 3	675
	21st to end	Day	16% 9% 29% 28% 13% 4	734
June	1st to 10th	Day	9% 5% 28% 31% 22% 6%	680
	11th to 20th	Day	10% 6% 30% 32% 19% 4	680
	21st to end	Day	11% 8% 31% 31% 15% 4	680
July	1st to 10th	Day	9% 3 19% 30% 25% 13%	671
	11th to 20th	Day	8% 3 25% 32% 24% 8%	668
	21st to end	Day	7% 3 22% 36% 28% 4	739
August	1st to 10th	Day	7% 3 23% 34% 27% 6%	676
	11th to 20th	Day	11% 4 20% 35% 23% 7%	656
	21st to end	Day	9% 3 18% 35% 28% 7%	539
September	1st to 10th	Day	15% 6% 19% 29% 24% 8%	490
	11th to 20th	Day	9% 4 20% 37% 22% 8%	490
	21st to end	Day	14% 9% 30% 23% 20% 4	319
October	1st to 10th	Day	19% 9% 27% 26% 14% 5%	300
	11th to 20th	Day	18% 21% 33% 20% 7% 1	300
	21st to end	Day	21% 14% 36% 20% 7% 2	330
November	1st to 10th	Day	15% 10% 44% 20% 10% 2	282
	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% 37% 26% 7%	950
	21st to end	Night	19% 12% 36% 27% 6%	1045
February	1st to 10th	Night	20% 9% 40% 24% 6%	950
	11th to 20th	Night	16% 12% 38% 29% 4	929
	21st to end	Night	20% 14% 40% 22% 4 1	636
March	1st to 10th	Night	19% 12% 39% 23% 6% 1	638
	11th to 20th	Night	18% 11% 35% 28% 8% 1	570
	21st to end	Night	23% 12% 38% 21% 6% 1	627
April	1st to 10th	Night	19% 13% 41% 24% 3	570
	11th to 20th	Night	20% 14% 34% 25% 6%	563
	21st to end	Night	21% 9% 36% 25% 8% 1	570
May	1st to 10th	Night	19% 6% 36% 31% 7% 1	570
	11th to 20th	Night	17% 10% 29% 32% 11%	561
	21st to end	Night	14% 6% 30% 33% 17%	617
June	1st to 10th	Night	9% 4 24% 45% 17% 1	570
	11th to 20th	Night	9% 4 25% 46% 16% 1	570
	21st to end	Night	10% 6% 28% 40% 15% 1	570
July	1st to 10th	Night	6% 1 14% 44% 32% 3	555
	11th to 20th	Night	5% 2 20% 43% 28% 2	552
	21st to end	Night	7% 2 17% 48% 24% 2	624
August	1st to 10th	Night	6% 1 17% 47% 26% 2	567
	11th to 20th	Night	8% 2 15% 45% 27% 3	564
	21st to end	Night	9% 2 15% 42% 30% 2	627
September	1st to 10th	Night	11% 3 21% 37% 24% 4	570
	11th to 20th	Night	13% 2 19% 39% 24% 3	570
	21st to end	Night	11% 5% 29% 35% 18% 1	670
October	1st to 10th	Night	16% 6% 28% 32% 16% 2	760
	11th to 20th	Night	15% 12% 34% 31% 8%	760
	21st to end	Night	20% 11% 34% 27% 8%	836
November	1st to 10th	Night	15% 9% 39% 29% 9% 1	760
	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 2024-11-03 01:11:21. Version ac07

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