New Bremen
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the New Bremen clear sky chart from 2005-11-06 to 2026-05-17.

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	14% 10% 4 9% 5% 5% 5% 4 6% 7% 33%	131775
	Night	14% 11% 4 9% 5% 4 4 4 5% 6% 34%	131154
Transparency	Day	48% 6% 11% 21% 13% 1	135387
	Night	49% 5% 11% 21% 13% 2	135613
Seeing	Day	18% 10% 27% 23% 15% 7%	17522
	Night	19% 10% 28% 28% 14% 2	27377

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	17% 16% 8% 16% 6% 5% 4 3 4 5% 17%	4691
	11th to 20th	Day	11% 16% 7% 13% 9% 7% 7% 4 4 4 20%	4780
	21st to end	Day	19% 15% 7% 14% 7% 5% 5% 3 4 5% 17%	5780
February	1st to 10th	Day	17% 17% 6% 12% 6% 5% 4 3 5% 5% 21%	1956
	11th to 20th	Day	15% 12% 5% 14% 7% 4 5% 3 5% 6% 24%	2048
	21st to end	Day	15% 15% 4 10% 5% 5% 4 3 4 7% 28%	1730
March	1st to 10th	Day	18% 15% 7% 11% 5% 4 4 3 3 4 26%	4616
	11th to 20th	Day	11% 10% 3 7% 4 4 5% 4 5% 7% 39%	5090
	21st to end	Day	17% 13% 4 11% 5% 5% 4 4 5% 6% 27%	5586
April	1st to 10th	Day	15% 11% 4 9% 6% 5% 4 4 5% 6% 30%	2488
	11th to 20th	Day	16% 9% 3 7% 5% 5% 4 4 5% 7% 35%	2577
	21st to end	Day	18% 9% 2 8% 5% 5% 4 4 5% 8% 32%	2730
May	1st to 10th	Day	21% 9% 3 8% 5% 5% 5% 3 6% 6% 29%	5992
	11th to 20th	Day	19% 7% 2 6% 5% 4 5% 3 6% 8% 35%	5939
	21st to end	Day	14% 7% 2 7% 5% 5% 5% 4 7% 9% 35%	6433
June	1st to 10th	Day	13% 6% 2 6% 5% 5% 5% 4 7% 8% 40%	2712
	11th to 20th	Day	10% 6% 2 6% 5% 4 6% 4 7% 10% 41%	2800
	21st to end	Day	9% 5% 2 6% 5% 4 5% 6% 8% 11% 39%	2800
July	1st to 10th	Day	10% 6% 2 7% 5% 5% 5% 4 7% 10% 39%	6360
	11th to 20th	Day	8% 5% 2 7% 5% 6% 5% 5% 8% 11% 37%	6360
	21st to end	Day	9% 6% 3 7% 5% 6% 6% 5% 8% 9% 36%	6424
August	1st to 10th	Day	8% 6% 2 6% 4 4 5% 4 8% 10% 44%	4234
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 4 9% 10% 42%	4174
	21st to end	Day	7% 5% 2 6% 4 4 5% 4 7% 10% 46%	4414
September	1st to 10th	Day	11% 6% 2 5% 5% 4 4 3 5% 7% 49%	2285
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 7% 9% 46%	2200
	21st to end	Day	16% 7% 3 6% 4 4 3 3 4 6% 45%	2200
October	1st to 10th	Day	11% 5% 3 7% 4 4 4 3 5% 6% 46%	2200
	11th to 20th	Day	14% 7% 2 6% 4 4 4 4 5% 7% 43%	2014
	21st to end	Day	19% 9% 3 8% 4 4 4 4 5% 7% 32%	2022
November	1st to 10th	Day	10% 8% 3 6% 3 3 4 3 5% 6% 48%	1852
	11th to 20th	Day	17% 12% 4 8% 5% 4 4 3 4 5% 33%	1890
	21st to end	Day	18% 15% 5% 9% 4 4 3 3 5% 5% 28%	1890
December	1st to 10th	Day	15% 14% 5% 9% 5% 5% 4 3 5% 5% 29%	3020
	11th to 20th	Day	16% 16% 6% 12% 6% 4 5% 4 5% 5% 22%	3418
	21st to end	Day	22% 20% 8% 12% 6% 5% 4 3 3 4 12%	4070
January	1st to 10th	Night	14% 16% 7% 16% 7% 5% 4 3 4 4 19%	8232
	11th to 20th	Night	10% 17% 9% 16% 7% 6% 6% 4 4 4 18%	8188
	21st to end	Night	18% 13% 5% 9% 5% 5% 5% 4 5% 6% 24%	8401
February	1st to 10th	Night	19% 14% 5% 9% 6% 5% 4 2 4 5% 25%	2662
	11th to 20th	Night	14% 14% 5% 10% 6% 5% 4 3 5% 6% 29%	2458
	21st to end	Night	19% 12% 5% 11% 5% 5% 3 3 5% 6% 27%	2076
March	1st to 10th	Night	19% 13% 4 7% 4 4 3 2 4 5% 36%	5457
	11th to 20th	Night	11% 7% 3 7% 4 4 5% 4 5% 8% 42%	5090
	21st to end	Night	17% 10% 4 8% 5% 4 4 3 4 5% 35%	5588
April	1st to 10th	Night	17% 10% 3 7% 4 4 4 4 5% 7% 35%	2149
	11th to 20th	Night	16% 8% 2 7% 5% 5% 5% 4 6% 8% 36%	1990
	21st to end	Night	17% 9% 3 7% 4 4 3 3 5% 7% 37%	1890
May	1st to 10th	Night	20% 11% 4 8% 5% 4 5% 3 5% 6% 29%	4123
	11th to 20th	Night	16% 8% 2 6% 5% 4 4 4 6% 10% 37%	4086
	21st to end	Night	12% 7% 3 6% 4 4 5% 4 6% 9% 39%	4421
June	1st to 10th	Night	9% 6% 3 6% 4 4 4 4 5% 9% 48%	1682
	11th to 20th	Night	9% 6% 2 5% 4 5% 4 4 5% 10% 46%	1600
	21st to end	Night	8% 6% 2 5% 5% 4 4 4 6% 10% 46%	1600
July	1st to 10th	Night	8% 5% 2 6% 5% 5% 5% 4 6% 9% 44%	3618
	11th to 20th	Night	7% 6% 2 6% 5% 5% 5% 4 7% 10% 44%	3617
	21st to end	Night	9% 6% 3 7% 5% 5% 5% 4 6% 9% 42%	4425
August	1st to 10th	Night	11% 7% 2 7% 4 4 5% 4 6% 8% 42%	2915
	11th to 20th	Night	7% 6% 3 6% 4 4 4 4 7% 8% 47%	2875
	21st to end	Night	5% 4 2 6% 5% 5% 5% 4 6% 8% 50%	3480
September	1st to 10th	Night	10% 5% 2 5% 3 3 4 3 5% 7% 51%	2094
	11th to 20th	Night	9% 5% 1 4 3 3 3 3 5% 7% 56%	2200
	21st to end	Night	12% 7% 2 6% 4 4 4 4 5% 6% 46%	2200
October	1st to 10th	Night	10% 5% 2 6% 3 3 4 4 5% 7% 52%	2200
	11th to 20th	Night	16% 8% 3 7% 4 4 3 3 4 7% 41%	2385
	21st to end	Night	18% 7% 2 7% 4 4 4 4 5% 6% 37%	2815
November	1st to 10th	Night	12% 9% 3 5% 4 3 3 3 5% 6% 46%	2666
	11th to 20th	Night	15% 12% 4 8% 4 4 3 3 6% 6% 36%	2730
	21st to end	Night	18% 15% 4 9% 5% 4 4 4 4 5% 27%	2730
December	1st to 10th	Night	14% 12% 4 9% 6% 5% 5% 5% 6% 7% 27%	4380
	11th to 20th	Night	17% 17% 8% 12% 5% 4 4 3 4 4 21%	4981
	21st to end	Night	23% 20% 7% 11% 5% 4 4 3 4 5% 14%	7150

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	70% 4 9% 12% 4	4692
	11th to 20th	Day	69% 3 8% 8% 11% 1	4780
	21st to end	Day	70% 3 9% 11% 6%	5780
February	1st to 10th	Day	65% 4 10% 13% 7% 1	1956
	11th to 20th	Day	62% 4 10% 17% 7%	2058
	21st to end	Day	57% 5% 12% 17% 8% 2	1730
March	1st to 10th	Day	62% 4 8% 18% 8% 1	4616
	11th to 20th	Day	44% 5% 10% 29% 12% 1	5090
	21st to end	Day	57% 5% 13% 17% 7% 2	5586
April	1st to 10th	Day	53% 7% 11% 18% 11%	2488
	11th to 20th	Day	48% 6% 12% 20% 12% 2	2577
	21st to end	Day	49% 6% 12% 20% 10% 2	2730
May	1st to 10th	Day	55% 7% 10% 16% 12% 1	6027
	11th to 20th	Day	46% 6% 13% 23% 11% 1	5943
	21st to end	Day	42% 8% 12% 24% 13% 1	6447
June	1st to 10th	Day	40% 7% 11% 24% 16% 2	2712
	11th to 20th	Day	37% 8% 13% 25% 16% 2	2800
	21st to end	Day	37% 9% 14% 21% 15% 4	2800
July	1st to 10th	Day	38% 6% 10% 26% 17% 2	6291
	11th to 20th	Day	37% 8% 15% 23% 16%	6285
	21st to end	Day	40% 8% 13% 20% 16% 2	6240
August	1st to 10th	Day	32% 8% 18% 27% 14% 1	4221
	11th to 20th	Day	33% 7% 12% 32% 15% 1	4213
	21st to end	Day	31% 7% 14% 31% 14% 3	4413
September	1st to 10th	Day	35% 7% 11% 22% 21% 4	2285
	11th to 20th	Day	33% 7% 9% 25% 23% 3	2200
	21st to end	Day	41% 5% 10% 21% 22% 1	2200
October	1st to 10th	Day	26% 5% 11% 31% 27% 1	3590
	11th to 20th	Day	32% 5% 12% 26% 24% 1	3254
	21st to end	Day	42% 4 10% 24% 20% 1	3246
November	1st to 10th	Day	37% 5% 12% 26% 18% 2	1852
	11th to 20th	Day	53% 4 9% 20% 11% 3	1890
	21st to end	Day	58% 5% 9% 18% 8% 1	1890
December	1st to 10th	Day	55% 4 14% 20% 7%	3020
	11th to 20th	Day	64% 4 12% 14% 5%	3415
	21st to end	Day	76% 3 7% 9% 4	4070
January	1st to 10th	Night	68% 4 9% 14% 5%	8233
	11th to 20th	Night	69% 3 8% 10% 9% 1	8188
	21st to end	Night	60% 3 12% 17% 7% 1	8401
February	1st to 10th	Night	62% 5% 10% 15% 7% 1	2662
	11th to 20th	Night	56% 5% 10% 17% 11% 1	2459
	21st to end	Night	59% 5% 10% 16% 9% 1	2076
March	1st to 10th	Night	53% 3 7% 26% 10% 1	5457
	11th to 20th	Night	40% 5% 13% 27% 13% 1	5090
	21st to end	Night	51% 4 9% 23% 11% 1	5588
April	1st to 10th	Night	48% 6% 12% 20% 13% 1	2149
	11th to 20th	Night	44% 8% 11% 18% 16% 3	1990
	21st to end	Night	47% 5% 10% 22% 13% 3	1890
May	1st to 10th	Night	55% 7% 8% 16% 10% 3	4150
	11th to 20th	Night	43% 8% 12% 24% 14% 1	4087
	21st to end	Night	39% 8% 13% 24% 13% 2	4429
June	1st to 10th	Night	34% 6% 11% 25% 21% 3	1682
	11th to 20th	Night	33% 8% 12% 26% 18% 3	1600
	21st to end	Night	32% 8% 16% 23% 18% 4	1600
July	1st to 10th	Night	35% 7% 12% 24% 18% 5%	3580
	11th to 20th	Night	34% 8% 15% 27% 16% 1	3572
	21st to end	Night	37% 6% 15% 19% 19% 3	4296
August	1st to 10th	Night	38% 7% 13% 26% 15% 1	2904
	11th to 20th	Night	33% 6% 11% 31% 18% 1	2902
	21st to end	Night	31% 8% 13% 27% 19% 3	3480
September	1st to 10th	Night	32% 6% 11% 26% 19% 5%	2094
	11th to 20th	Night	28% 5% 9% 29% 26% 3	2200
	21st to end	Night	36% 7% 10% 22% 23% 2	2200
October	1st to 10th	Night	23% 4 8% 30% 34% 2	3590
	11th to 20th	Night	33% 4 11% 26% 26% 1	3884
	21st to end	Night	35% 4 7% 29% 21% 3	4541
November	1st to 10th	Night	38% 4 11% 24% 20% 2	2666
	11th to 20th	Night	48% 5% 10% 21% 14% 3	2730
	21st to end	Night	59% 5% 10% 18% 7%	2730
December	1st to 10th	Night	54% 4 12% 22% 7% 1	4380
	11th to 20th	Night	66% 4 11% 12% 7%	4983
	21st to end	Night	73% 5% 9% 10% 3	7150

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% 19% 33% 18% 4	330
	11th to 20th	Day	25% 20% 37% 14% 3 1	330
	21st to end	Day	31% 18% 29% 17% 5%	363
February	1st to 10th	Day	28% 15% 35% 17% 4 1	330
	11th to 20th	Day	25% 20% 35% 14% 5%	330
	21st to end	Day	22% 17% 47% 14% 1	273
March	1st to 10th	Day	25% 18% 39% 16% 3	340
	11th to 20th	Day	26% 14% 31% 21% 6% 1	540
	21st to end	Day	29% 16% 30% 19% 5%	594
April	1st to 10th	Day	21% 19% 31% 20% 8% 1	540
	11th to 20th	Day	20% 18% 30% 20% 8% 3	532
	21st to end	Day	22% 12% 32% 22% 10% 2	540
May	1st to 10th	Day	24% 11% 34% 20% 8% 3	543
	11th to 20th	Day	23% 8% 26% 24% 12% 7%	551
	21st to end	Day	12% 8% 27% 27% 17% 9%	573
June	1st to 10th	Day	14% 6% 25% 31% 18% 7%	642
	11th to 20th	Day	12% 6% 23% 31% 22% 7%	730
	21st to end	Day	12% 5% 25% 29% 21% 8%	730
July	1st to 10th	Day	12% 3 17% 27% 23% 18%	721
	11th to 20th	Day	7% 4 19% 30% 25% 14%	718
	21st to end	Day	11% 2 16% 26% 28% 16%	576
August	1st to 10th	Day	8% 4 14% 25% 32% 17%	526
	11th to 20th	Day	12% 2 17% 29% 26% 14%	519
	21st to end	Day	9% 3 14% 29% 32% 14%	583
September	1st to 10th	Day	12% 5% 15% 25% 30% 13%	530
	11th to 20th	Day	8% 2 12% 27% 31% 19%	530
	21st to end	Day	20% 8% 20% 21% 21% 10%	530
October	1st to 10th	Day	12% 6% 23% 29% 18% 12%	530
	11th to 20th	Day	16% 12% 30% 25% 13% 3	530
	21st to end	Day	27% 10% 34% 23% 4 1	405
November	1st to 10th	Day	16% 15% 35% 22% 8% 4	330
	11th to 20th	Day	26% 16% 31% 17% 9% 1	330
	21st to end	Day	28% 13% 40% 15% 3	330
December	1st to 10th	Day	20% 20% 37% 18% 5% 1	330
	11th to 20th	Day	22% 17% 42% 15% 4	330
	21st to end	Day	29% 19% 34% 16% 2	363
January	1st to 10th	Night	24% 15% 36% 20% 5%	1050
	11th to 20th	Night	25% 16% 37% 17% 5%	1023
	21st to end	Night	24% 14% 36% 22% 4	924
February	1st to 10th	Night	25% 12% 35% 25% 3	840
	11th to 20th	Night	21% 14% 38% 25% 2	823
	21st to end	Night	25% 14% 38% 21% 3	692
March	1st to 10th	Night	22% 14% 34% 24% 6%	840
	11th to 20th	Night	18% 16% 35% 25% 6% 1	840
	21st to end	Night	22% 14% 31% 26% 7%	924
April	1st to 10th	Night	23% 12% 32% 28% 5% 1	679
	11th to 20th	Night	20% 11% 33% 26% 9% 1	623
	21st to end	Night	20% 8% 36% 26% 9% 1	630
May	1st to 10th	Night	23% 8% 33% 27% 9% 1	630
	11th to 20th	Night	21% 6% 26% 30% 15% 2	609
	21st to end	Night	9% 4 23% 37% 24% 3	650
June	1st to 10th	Night	11% 3 24% 42% 21% 1	600
	11th to 20th	Night	12% 3 20% 41% 23% 1	600
	21st to end	Night	9% 3 23% 36% 28% 2	600
July	1st to 10th	Night	11% 1 14% 37% 31% 5%	585
	11th to 20th	Night	9% 2 17% 38% 29% 5%	582
	21st to end	Night	10% 2 11% 40% 35% 3	657
August	1st to 10th	Night	8% 2 10% 41% 34% 4	597
	11th to 20th	Night	8% 2 12% 40% 34% 5%	594
	21st to end	Night	8% 2 11% 37% 37% 5%	660
September	1st to 10th	Night	12% 4 15% 34% 31% 4	694
	11th to 20th	Night	11% 3 13% 33% 35% 5%	800
	21st to end	Night	15% 5% 23% 32% 23% 3	800
October	1st to 10th	Night	13% 4 24% 34% 21% 4	800
	11th to 20th	Night	21% 11% 27% 28% 13%	800
	21st to end	Night	22% 11% 32% 27% 8%	880
November	1st to 10th	Night	17% 9% 34% 26% 13% 1	820
	11th to 20th	Night	20% 16% 33% 24% 6% 1	840
	21st to end	Night	25% 15% 30% 24% 6%	840
December	1st to 10th	Night	25% 14% 34% 22% 5%	840
	11th to 20th	Night	25% 13% 35% 22% 5%	856
	21st to end	Night	30% 15% 32% 20% 3	1155

Page generated at 2026-05-14 01:58:59. Version ac07

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