Bucyrus
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bucyrus clear sky chart from 2005-11-06 to 2026-06-16.

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	15% 11% 4 9% 5% 5% 5% 4 5% 7% 31%	138502
	Night	15% 11% 4 9% 5% 4 4 3 5% 6% 32%	133547
Transparency	Day	51% 6% 11% 19% 12% 1	142130
	Night	51% 5% 11% 20% 12% 2	137991
Seeing	Day	18% 11% 28% 23% 14% 6%	17502
	Night	20% 9% 28% 29% 13% 1	27002

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	16% 18% 8% 19% 7% 5% 4 3 4 5% 11%	5255
	11th to 20th	Day	11% 19% 6% 16% 8% 7% 7% 3 3 3 16%	5280
	21st to end	Day	19% 16% 8% 14% 8% 7% 5% 4 4 4 13%	5780
February	1st to 10th	Day	17% 16% 6% 14% 8% 5% 3 3 4 5% 20%	1890
	11th to 20th	Day	14% 13% 7% 15% 7% 4 5% 3 4 6% 22%	2006
	21st to end	Day	16% 14% 5% 11% 5% 5% 5% 4 5% 6% 27%	1730
March	1st to 10th	Day	17% 13% 7% 13% 6% 4 4 3 4 4 25%	4765
	11th to 20th	Day	11% 12% 4 9% 5% 5% 4 3 4 7% 37%	5090
	21st to end	Day	19% 13% 5% 10% 5% 4 4 3 4 6% 25%	5586
April	1st to 10th	Day	14% 14% 3 8% 5% 4 5% 4 6% 7% 29%	2380
	11th to 20th	Day	16% 11% 3 7% 6% 4 4 4 5% 6% 34%	2660
	21st to end	Day	18% 10% 3 7% 5% 4 4 3 5% 7% 33%	2730
May	1st to 10th	Day	21% 10% 3 7% 5% 5% 5% 4 6% 6% 28%	7616
	11th to 20th	Day	16% 8% 3 7% 5% 5% 5% 4 6% 8% 33%	7626
	21st to end	Day	18% 7% 2 6% 4 5% 5% 4 5% 7% 37%	8391
June	1st to 10th	Day	13% 7% 3 6% 4 5% 5% 5% 7% 8% 38%	2730
	11th to 20th	Day	11% 7% 3 7% 6% 5% 5% 4 7% 8% 37%	2825
	21st to end	Day	10% 5% 2 6% 6% 5% 5% 5% 8% 10% 38%	2800
July	1st to 10th	Day	9% 6% 2 7% 5% 5% 5% 4 7% 10% 40%	6360
	11th to 20th	Day	10% 5% 2 7% 5% 5% 6% 5% 8% 10% 37%	6002
	21st to end	Day	10% 6% 2 7% 5% 5% 6% 5% 7% 9% 38%	6424
August	1st to 10th	Day	9% 6% 3 7% 4 5% 5% 5% 7% 10% 38%	4234
	11th to 20th	Day	9% 5% 2 6% 4 5% 5% 5% 8% 11% 39%	4174
	21st to end	Day	8% 5% 2 6% 5% 5% 5% 4 7% 10% 43%	4618
September	1st to 10th	Day	12% 5% 2 6% 4 4 5% 3 4 7% 48%	2220
	11th to 20th	Day	9% 5% 2 7% 4 4 4 3 5% 8% 48%	2200
	21st to end	Day	18% 8% 3 6% 4 3 3 3 5% 6% 42%	2200
October	1st to 10th	Day	13% 8% 2 6% 4 4 4 3 5% 7% 43%	2140
	11th to 20th	Day	15% 9% 3 8% 4 3 5% 4 6% 7% 39%	2000
	21st to end	Day	20% 11% 3 6% 5% 5% 4 3 5% 7% 30%	2110
November	1st to 10th	Day	12% 9% 3 6% 5% 4 4 3 5% 6% 42%	1852
	11th to 20th	Day	18% 14% 4 7% 4 4 4 3 5% 6% 31%	1890
	21st to end	Day	18% 17% 6% 9% 4 5% 3 2 4 6% 26%	1890
December	1st to 10th	Day	16% 16% 7% 15% 6% 4 3 3 4 5% 20%	3020
	11th to 20th	Day	19% 19% 8% 11% 5% 4 4 3 4 5% 19%	3463
	21st to end	Day	24% 23% 7% 12% 5% 4 3 3 3 3 12%	4565
January	1st to 10th	Night	15% 20% 8% 17% 6% 5% 4 3 4 4 15%	7635
	11th to 20th	Night	9% 18% 10% 18% 7% 6% 6% 4 4 4 14%	7680
	21st to end	Night	18% 16% 6% 11% 5% 5% 5% 3 5% 6% 21%	8401
February	1st to 10th	Night	18% 14% 6% 12% 6% 5% 4 4 4 5% 22%	2730
	11th to 20th	Night	16% 15% 5% 12% 7% 5% 4 3 5% 5% 24%	2495
	21st to end	Night	19% 14% 5% 11% 6% 4 4 3 3 4 26%	2076
March	1st to 10th	Night	18% 14% 4 8% 5% 4 3 3 4 5% 33%	5306
	11th to 20th	Night	12% 8% 3 6% 4 4 5% 4 6% 8% 40%	5090
	21st to end	Night	17% 10% 3 8% 5% 4 4 3 5% 6% 35%	5588
April	1st to 10th	Night	17% 12% 3 8% 5% 4 5% 4 5% 6% 32%	2258
	11th to 20th	Night	16% 8% 3 7% 5% 4 4 4 6% 7% 36%	1907
	21st to end	Night	16% 9% 3 7% 5% 5% 4 3 5% 7% 36%	1890
May	1st to 10th	Night	24% 10% 3 8% 5% 5% 5% 3 5% 6% 27%	5237
	11th to 20th	Night	16% 7% 3 8% 4 4 4 4 5% 9% 38%	5234
	21st to end	Night	16% 7% 2 6% 4 4 4 3 6% 7% 39%	5761
June	1st to 10th	Night	10% 7% 2 6% 4 4 5% 4 5% 7% 46%	1890
	11th to 20th	Night	7% 6% 2 6% 4 5% 5% 5% 7% 10% 43%	1679
	21st to end	Night	9% 4 2 5% 6% 4 5% 5% 6% 10% 44%	1600
July	1st to 10th	Night	9% 5% 2 6% 4 4 5% 4 7% 9% 46%	3618
	11th to 20th	Night	10% 5% 2 7% 4 4 5% 5% 6% 9% 44%	3942
	21st to end	Night	9% 6% 2 7% 4 5% 4 4 6% 9% 45%	4427
August	1st to 10th	Night	10% 6% 3 8% 4 5% 5% 5% 8% 9% 38%	2915
	11th to 20th	Night	10% 8% 2 7% 4 4 4 3 6% 8% 43%	2875
	21st to end	Night	6% 4 2 5% 4 5% 6% 5% 6% 8% 49%	3277
September	1st to 10th	Night	10% 6% 2 5% 4 3 4 3 5% 7% 52%	2160
	11th to 20th	Night	10% 5% 2 4 3 4 3 3 5% 7% 56%	2200
	21st to end	Night	16% 7% 2 5% 3 4 4 3 5% 6% 45%	2200
October	1st to 10th	Night	11% 5% 2 5% 4 5% 4 3 5% 7% 49%	2260
	11th to 20th	Night	17% 8% 3 7% 4 4 4 3 4 6% 40%	2400
	21st to end	Night	21% 8% 3 6% 4 4 5% 3 4 6% 36%	2725
November	1st to 10th	Night	13% 8% 3 6% 4 4 4 3 5% 6% 44%	2666
	11th to 20th	Night	15% 13% 4 8% 4 4 4 3 4 7% 34%	2730
	21st to end	Night	19% 16% 4 8% 4 4 4 4 5% 6% 26%	2730
December	1st to 10th	Night	15% 13% 6% 14% 7% 5% 4 3 5% 5% 23%	4380
	11th to 20th	Night	19% 19% 7% 11% 5% 3 4 3 4 5% 20%	4952
	21st to end	Night	23% 21% 7% 11% 4 3 4 3 4 5% 14%	6633

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	76% 4 10% 8% 2	5256
	11th to 20th	Day	74% 3 7% 6% 9%	5280
	21st to end	Day	76% 3 6% 10% 4	5780
February	1st to 10th	Day	67% 4 8% 14% 6%	1890
	11th to 20th	Day	64% 5% 7% 16% 7% 1	2016
	21st to end	Day	60% 5% 13% 15% 6% 2	1730
March	1st to 10th	Day	62% 5% 7% 20% 6%	4765
	11th to 20th	Day	48% 4 13% 25% 9% 1	5090
	21st to end	Day	60% 4 11% 16% 8% 1	5586
April	1st to 10th	Day	53% 6% 13% 16% 11% 1	2380
	11th to 20th	Day	50% 6% 13% 18% 12% 2	2660
	21st to end	Day	51% 5% 11% 21% 10% 2	2730
May	1st to 10th	Day	54% 7% 11% 18% 10% 1	7651
	11th to 20th	Day	47% 7% 13% 22% 11% 1	7630
	21st to end	Day	45% 6% 10% 19% 16% 4	8405
June	1st to 10th	Day	42% 7% 11% 25% 14% 2	2730
	11th to 20th	Day	42% 8% 13% 21% 15% 1	2825
	21st to end	Day	39% 9% 14% 21% 15% 3	2800
July	1st to 10th	Day	37% 7% 10% 28% 16% 2	6291
	11th to 20th	Day	38% 9% 15% 21% 15% 1	5930
	21st to end	Day	39% 8% 13% 18% 19% 3	6240
August	1st to 10th	Day	39% 8% 15% 24% 14% 1	4221
	11th to 20th	Day	36% 8% 13% 30% 13% 1	4213
	21st to end	Day	35% 7% 14% 29% 12% 3	4617
September	1st to 10th	Day	36% 7% 11% 23% 19% 4	2220
	11th to 20th	Day	36% 6% 11% 26% 20% 2	2200
	21st to end	Day	44% 5% 11% 20% 20% 1	2200
October	1st to 10th	Day	28% 5% 12% 31% 23% 1	3491
	11th to 20th	Day	38% 5% 10% 24% 21% 2	3240
	21st to end	Day	43% 4 11% 21% 19% 1	3386
November	1st to 10th	Day	43% 4 12% 23% 15% 2	1852
	11th to 20th	Day	55% 4 10% 20% 10% 2	1890
	21st to end	Day	61% 4 10% 17% 8% 1	1890
December	1st to 10th	Day	67% 5% 13% 12% 3	3020
	11th to 20th	Day	68% 3 10% 14% 4	3460
	21st to end	Day	79% 3 7% 8% 4	4565
January	1st to 10th	Night	74% 4 7% 12% 3	7636
	11th to 20th	Night	74% 4 7% 8% 7% 1	7680
	21st to end	Night	65% 4 12% 13% 7% 1	8401
February	1st to 10th	Night	65% 4 9% 14% 7% 1	2730
	11th to 20th	Night	62% 3 10% 16% 8% 1	2496
	21st to end	Night	62% 4 9% 16% 8% 1	2076
March	1st to 10th	Night	55% 4 10% 21% 9% 1	5306
	11th to 20th	Night	40% 5% 14% 28% 11% 1	5090
	21st to end	Night	50% 4 10% 21% 14% 1	5588
April	1st to 10th	Night	52% 5% 12% 16% 13% 2	2258
	11th to 20th	Night	46% 5% 12% 18% 17% 2	1907
	21st to end	Night	47% 6% 10% 22% 14% 2	1890
May	1st to 10th	Night	57% 7% 9% 15% 11% 2	5264
	11th to 20th	Night	44% 7% 11% 23% 15% 1	5235
	21st to end	Night	42% 6% 11% 22% 14% 4	5771
June	1st to 10th	Night	38% 6% 11% 23% 18% 4	1890
	11th to 20th	Night	34% 8% 14% 25% 16% 3	1679
	21st to end	Night	34% 8% 14% 25% 16% 4	1600
July	1st to 10th	Night	34% 7% 12% 26% 17% 4	3580
	11th to 20th	Night	35% 7% 15% 27% 15% 1	3894
	21st to end	Night	36% 6% 14% 20% 23% 2	4297
August	1st to 10th	Night	39% 8% 13% 23% 15% 1	2904
	11th to 20th	Night	38% 6% 10% 28% 17% 1	2902
	21st to end	Night	31% 7% 13% 30% 16% 3	3277
September	1st to 10th	Night	33% 6% 11% 27% 18% 5%	2160
	11th to 20th	Night	28% 5% 10% 28% 25% 3	2200
	21st to end	Night	40% 6% 10% 22% 20% 3	2200
October	1st to 10th	Night	26% 4 7% 29% 32% 1	3689
	11th to 20th	Night	36% 4 9% 26% 21% 3	3899
	21st to end	Night	38% 3 9% 28% 19% 3	4399
November	1st to 10th	Night	42% 4 12% 24% 17% 2	2666
	11th to 20th	Night	51% 4 10% 21% 12% 2	2730
	21st to end	Night	60% 4 12% 17% 7% 1	2730
December	1st to 10th	Night	63% 5% 10% 16% 6% 1	4380
	11th to 20th	Night	68% 3 12% 12% 4	4954
	21st to end	Night	73% 4 10% 10% 4	6633

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	25% 18% 36% 16% 5% 1	330
	11th to 20th	Day	21% 24% 41% 10% 4 1	330
	21st to end	Day	24% 22% 30% 20% 3	363
February	1st to 10th	Day	28% 13% 39% 16% 4 1	330
	11th to 20th	Day	26% 18% 33% 21% 2	330
	21st to end	Day	21% 24% 40% 14% 1	273
March	1st to 10th	Day	23% 18% 37% 18% 4	411
	11th to 20th	Day	24% 18% 35% 18% 5% 1	540
	21st to end	Day	29% 15% 31% 21% 4 1	594
April	1st to 10th	Day	21% 16% 35% 19% 7% 1	540
	11th to 20th	Day	20% 20% 30% 18% 9% 4	532
	21st to end	Day	23% 15% 31% 21% 9% 2	540
May	1st to 10th	Day	26% 12% 30% 22% 8% 2	543
	11th to 20th	Day	22% 8% 30% 23% 11% 5%	567
	21st to end	Day	14% 7% 26% 24% 19% 9%	617
June	1st to 10th	Day	14% 6% 26% 32% 16% 6%	570
	11th to 20th	Day	14% 7% 27% 28% 19% 5%	710
	21st to end	Day	13% 7% 26% 28% 20% 6%	730
July	1st to 10th	Day	12% 3 20% 28% 22% 15%	721
	11th to 20th	Day	11% 4 21% 28% 24% 12%	571
	21st to end	Day	11% 3 17% 27% 29% 12%	576
August	1st to 10th	Day	10% 4 15% 25% 29% 16%	526
	11th to 20th	Day	11% 4 19% 29% 25% 12%	519
	21st to end	Day	11% 4 16% 27% 28% 14%	583
September	1st to 10th	Day	14% 3 19% 25% 26% 13%	530
	11th to 20th	Day	10% 3 14% 22% 32% 19%	530
	21st to end	Day	20% 8% 20% 24% 18% 10%	530
October	1st to 10th	Day	12% 8% 24% 25% 20% 10%	530
	11th to 20th	Day	15% 15% 32% 24% 11% 3	530
	21st to end	Day	25% 14% 36% 19% 6% 1	493
November	1st to 10th	Day	16% 16% 35% 21% 10% 2	330
	11th to 20th	Day	26% 19% 32% 15% 7% 1	330
	21st to end	Day	28% 19% 34% 18% 1	330
December	1st to 10th	Day	23% 20% 35% 16% 5% 1	330
	11th to 20th	Day	25% 20% 36% 17% 2	330
	21st to end	Day	33% 17% 32% 16% 2	363
January	1st to 10th	Night	25% 16% 36% 19% 4	840
	11th to 20th	Night	27% 17% 38% 16% 3 1	840
	21st to end	Night	23% 16% 37% 20% 3	924
February	1st to 10th	Night	23% 14% 38% 22% 3	840
	11th to 20th	Night	24% 14% 34% 24% 3	823
	21st to end	Night	27% 13% 40% 17% 2	692
March	1st to 10th	Night	24% 13% 35% 22% 6%	840
	11th to 20th	Night	20% 15% 35% 23% 5% 1	840
	21st to end	Night	24% 11% 34% 25% 6%	924
April	1st to 10th	Night	23% 13% 34% 24% 5% 1	788
	11th to 20th	Night	21% 12% 35% 24% 8% 1	623
	21st to end	Night	21% 8% 37% 25% 8% 1	630
May	1st to 10th	Night	23% 7% 31% 30% 8% 1	630
	11th to 20th	Night	21% 5% 29% 32% 12% 2	621
	21st to end	Night	13% 3 24% 39% 20% 2	683
June	1st to 10th	Night	11% 3 26% 41% 17% 1	630
	11th to 20th	Night	12% 4 19% 44% 20% 1	615
	21st to end	Night	11% 4 21% 41% 22% 1	600
July	1st to 10th	Night	10% 2 14% 43% 28% 3	585
	11th to 20th	Night	9% 2 17% 41% 27% 4	582
	21st to end	Night	9% 2 13% 42% 31% 3	657
August	1st to 10th	Night	8% 2 12% 47% 29% 4	597
	11th to 20th	Night	12% 3 11% 39% 31% 4	594
	21st to end	Night	8% 2 12% 39% 34% 5%	660
September	1st to 10th	Night	12% 4 16% 36% 28% 5%	760
	11th to 20th	Night	12% 3 13% 37% 31% 6%	800
	21st to end	Night	18% 6% 21% 31% 21% 3	800
October	1st to 10th	Night	13% 6% 24% 34% 20% 2	800
	11th to 20th	Night	21% 10% 30% 28% 11% 1	800
	21st to end	Night	26% 11% 30% 26% 8%	880
November	1st to 10th	Night	18% 8% 35% 27% 12% 1	820
	11th to 20th	Night	23% 14% 32% 24% 5% 2	840
	21st to end	Night	27% 11% 34% 22% 5%	840
December	1st to 10th	Night	26% 15% 33% 20% 5%	840
	11th to 20th	Night	26% 13% 36% 21% 4	840
	21st to end	Night	29% 15% 32% 21% 3	924

Page generated at 2026-06-13 02:31:43. Version ac07

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