New Ulm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the New Ulm clear sky chart from 2005-11-06 to 2026-01-17.

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	12% 8% 3 8% 5% 4 4 4 5% 7% 39%	128333
	Night	12% 8% 3 8% 5% 4 4 4 5% 6% 40%	123590
Transparency	Day	45% 3 13% 26% 12% 1	131928
	Night	45% 3 12% 26% 14% 2	128072
Seeing	Day	17% 9% 30% 27% 13% 3	17603
	Night	16% 8% 32% 32% 11% 1	27576

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	8% 15% 5% 18% 10% 7% 5% 3 4 6% 19%	3697
	11th to 20th	Day	7% 12% 6% 11% 6% 6% 9% 7% 10% 7% 19%	3946
	21st to end	Day	5% 15% 7% 14% 6% 5% 5% 3 4 5% 30%	4488
February	1st to 10th	Day	8% 12% 5% 11% 8% 8% 6% 5% 6% 7% 26%	1800
	11th to 20th	Day	8% 13% 3 10% 7% 6% 6% 5% 7% 5% 31%	1754
	21st to end	Day	12% 11% 4 9% 6% 4 3 4 6% 8% 32%	1528
March	1st to 10th	Day	13% 8% 2 6% 4 4 4 3 5% 7% 44%	4936
	11th to 20th	Day	10% 10% 3 5% 3 3 4 3 5% 8% 45%	4980
	21st to end	Day	24% 11% 5% 10% 6% 4 4 3 4 6% 23%	5462
April	1st to 10th	Day	18% 10% 4 6% 4 3 4 3 6% 7% 35%	2368
	11th to 20th	Day	18% 12% 3 7% 5% 4 4 3 5% 6% 32%	2444
	21st to end	Day	24% 10% 3 6% 5% 4 4 3 5% 5% 31%	2600
May	1st to 10th	Day	13% 5% 2 5% 4 4 4 4 6% 6% 47%	5896
	11th to 20th	Day	18% 7% 2 5% 3 3 3 3 5% 6% 45%	6319
	21st to end	Day	18% 7% 3 7% 5% 5% 4 4 6% 7% 37%	6935
June	1st to 10th	Day	11% 5% 2 5% 4 4 5% 3 6% 9% 46%	2800
	11th to 20th	Day	14% 6% 2 7% 4 5% 4 4 7% 8% 40%	2871
	21st to end	Day	10% 5% 2 6% 4 5% 4 5% 6% 9% 44%	3000
July	1st to 10th	Day	8% 5% 2 6% 4 4 5% 4 7% 11% 45%	6651
	11th to 20th	Day	7% 4 2 5% 3 3 3 3 5% 8% 56%	6360
	21st to end	Day	7% 4 2 6% 4 4 5% 4 6% 11% 47%	6561
August	1st to 10th	Day	12% 6% 2 6% 4 4 4 4 6% 8% 44%	4234
	11th to 20th	Day	11% 6% 2 6% 5% 4 5% 4 7% 9% 40%	4171
	21st to end	Day	8% 5% 2 6% 4 4 5% 3 5% 7% 51%	4544
September	1st to 10th	Day	12% 5% 2 5% 4 4 4 4 5% 8% 49%	2400
	11th to 20th	Day	11% 6% 2 4 5% 4 5% 3 5% 8% 48%	2285
	21st to end	Day	13% 6% 1 6% 3 3 3 3 5% 7% 49%	2155
October	1st to 10th	Day	14% 7% 2 6% 4 4 4 3 5% 6% 45%	2000
	11th to 20th	Day	15% 8% 3 6% 3 4 4 3 4 6% 45%	2000
	21st to end	Day	18% 8% 3 7% 4 3 3 3 5% 6% 41%	2200
November	1st to 10th	Day	12% 9% 3 7% 4 4 3 3 5% 8% 41%	1740
	11th to 20th	Day	10% 12% 5% 9% 6% 4 4 4 4 6% 35%	1680
	21st to end	Day	14% 9% 3 10% 4 4 4 3 7% 8% 35%	1680
December	1st to 10th	Day	6% 10% 3 11% 9% 8% 6% 5% 6% 7% 29%	2690
	11th to 20th	Day	11% 14% 5% 12% 8% 7% 5% 4 5% 6% 23%	3088
	21st to end	Day	19% 16% 6% 20% 5% 4 4 3 3 5% 16%	4070
January	1st to 10th	Night	7% 11% 6% 19% 7% 8% 6% 4 5% 5% 23%	6488
	11th to 20th	Night	5% 10% 4 12% 7% 7% 10% 8% 8% 7% 22%	6149
	21st to end	Night	7% 15% 7% 11% 5% 5% 4 3 4 5% 34%	6490
February	1st to 10th	Night	9% 12% 4 9% 7% 6% 5% 3 4 7% 34%	2600
	11th to 20th	Night	8% 9% 3 9% 4 6% 5% 4 6% 7% 38%	2533
	21st to end	Night	11% 8% 3 8% 5% 5% 5% 4 6% 8% 37%	2117
March	1st to 10th	Night	10% 7% 2 6% 4 3 3 3 4 6% 52%	4919
	11th to 20th	Night	11% 6% 2 6% 4 4 5% 4 6% 9% 44%	4980
	21st to end	Night	25% 11% 3 9% 4 4 3 3 4 5% 30%	5467
April	1st to 10th	Night	13% 11% 3 6% 4 4 4 3 5% 7% 38%	2031
	11th to 20th	Night	19% 9% 3 7% 4 4 3 4 5% 6% 37%	1903
	21st to end	Night	20% 8% 3 6% 4 4 4 4 5% 5% 38%	1800
May	1st to 10th	Night	11% 6% 2 4 3 3 3 3 4 6% 55%	4017
	11th to 20th	Night	15% 7% 2 4 3 3 4 3 5% 6% 48%	3596
	21st to end	Night	19% 7% 2 6% 4 3 4 3 4 6% 41%	3942
June	1st to 10th	Night	10% 4 1 5% 3 4 4 4 6% 6% 53%	1600
	11th to 20th	Night	11% 4 2 6% 5% 4 4 5% 6% 6% 45%	1520
	21st to end	Night	9% 4 2 4 4 3 3 3 5% 8% 55%	1400
July	1st to 10th	Night	6% 4 1 5% 4 4 4 4 6% 10% 50%	3305
	11th to 20th	Night	5% 3 2 5% 4 4 4 4 6% 8% 55%	3617
	21st to end	Night	8% 4 2 5% 4 4 4 3 6% 8% 52%	4307
August	1st to 10th	Night	12% 6% 2 6% 3 4 4 3 5% 6% 49%	2926
	11th to 20th	Night	12% 4 2 4 4 3 3 3 6% 7% 51%	2888
	21st to end	Night	9% 5% 2 6% 3 3 4 3 5% 8% 52%	3360
September	1st to 10th	Night	9% 4 1 5% 3 3 3 3 4 7% 58%	2000
	11th to 20th	Night	10% 4 1 4 3 3 3 3 6% 9% 54%	2110
	21st to end	Night	10% 5% 2 5% 3 3 4 3 5% 6% 55%	2224
October	1st to 10th	Night	13% 6% 2 4 4 3 4 2 4 6% 52%	2400
	11th to 20th	Night	16% 7% 2 6% 4 3 3 3 4 6% 45%	2400
	21st to end	Night	16% 9% 3 7% 4 3 3 3 5% 5% 42%	2640
November	1st to 10th	Night	13% 7% 2 6% 4 4 4 3 5% 7% 45%	2772
	11th to 20th	Night	11% 11% 4 8% 5% 4 4 3 4 5% 39%	2940
	21st to end	Night	12% 10% 4 9% 5% 4 3 4 4 7% 39%	2940
December	1st to 10th	Night	6% 8% 4 12% 8% 6% 5% 4 6% 7% 34%	4720
	11th to 20th	Night	11% 12% 5% 13% 7% 5% 5% 4 5% 6% 27%	5339
	21st to end	Night	21% 14% 6% 16% 5% 4 4 3 4 5% 18%	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	69% 2 9% 14% 6%	3698
	11th to 20th	Day	59% 2 10% 18% 10%	3946
	21st to end	Day	59% 2 15% 15% 9%	4488
February	1st to 10th	Day	58% 2 11% 19% 9% 1	1800
	11th to 20th	Day	53% 4 12% 22% 8% 1	1763
	21st to end	Day	51% 3 15% 19% 11%	1528
March	1st to 10th	Day	42% 2 15% 29% 11% 2	4936
	11th to 20th	Day	39% 2 13% 31% 13% 2	4980
	21st to end	Day	64% 2 10% 19% 5%	5464
April	1st to 10th	Day	49% 2 12% 25% 10% 1	2368
	11th to 20th	Day	54% 2 10% 21% 11% 1	2444
	21st to end	Day	55% 2 10% 23% 8% 1	2600
May	1st to 10th	Day	39% 2 10% 31% 18% 1	5934
	11th to 20th	Day	42% 2 8% 23% 19% 6%	6323
	21st to end	Day	48% 2 9% 30% 10% 1	6949
June	1st to 10th	Day	35% 3 15% 31% 15% 1	2800
	11th to 20th	Day	43% 3 13% 24% 15% 2	2871
	21st to end	Day	37% 3 16% 28% 14% 2	3000
July	1st to 10th	Day	32% 5% 19% 32% 11%	6580
	11th to 20th	Day	28% 4 15% 36% 16% 1	6285
	21st to end	Day	31% 6% 17% 31% 14% 1	6375
August	1st to 10th	Day	40% 3 12% 31% 12% 2	4220
	11th to 20th	Day	40% 5% 17% 30% 8%	4210
	21st to end	Day	33% 5% 16% 30% 14% 1	4543
September	1st to 10th	Day	35% 3 13% 33% 17%	2400
	11th to 20th	Day	36% 2 16% 33% 12% 1	2285
	21st to end	Day	36% 2 11% 34% 15% 1	2155
October	1st to 10th	Day	30% 2 7% 34% 26% 1	3260
	11th to 20th	Day	38% 2 11% 25% 21% 2	3240
	21st to end	Day	42% 2 13% 30% 12% 1	3538
November	1st to 10th	Day	43% 2 15% 23% 15% 3	1740
	11th to 20th	Day	52% 3 13% 22% 10% 1	1680
	21st to end	Day	47% 3 18% 23% 8% 1	1680
December	1st to 10th	Day	54% 5% 14% 20% 7%	2690
	11th to 20th	Day	62% 3 16% 14% 5%	3085
	21st to end	Day	74% 1 9% 11% 4	4070
January	1st to 10th	Night	64% 3 10% 18% 6%	6488
	11th to 20th	Night	59% 3 11% 15% 11% 1	6149
	21st to end	Night	54% 2 12% 21% 10%	6490
February	1st to 10th	Night	53% 2 12% 23% 10% 2	2600
	11th to 20th	Night	46% 3 13% 25% 12% 2	2534
	21st to end	Night	45% 3 12% 25% 13% 2	2117
March	1st to 10th	Night	36% 2 10% 35% 15% 2	4919
	11th to 20th	Night	39% 2 11% 32% 16% 1	4980
	21st to end	Night	59% 2 10% 19% 8% 1	5467
April	1st to 10th	Night	47% 3 12% 25% 13% 1	2031
	11th to 20th	Night	49% 1 8% 21% 18% 2	1903
	21st to end	Night	49% 2 8% 24% 15% 2	1800
May	1st to 10th	Night	33% 2 10% 30% 23% 2	4044
	11th to 20th	Night	38% 2 7% 23% 21% 9%	3597
	21st to end	Night	46% 2 9% 29% 13% 1	3950
June	1st to 10th	Night	31% 3 15% 31% 18% 3	1600
	11th to 20th	Night	38% 4 14% 22% 19% 3	1520
	21st to end	Night	29% 3 16% 31% 19% 3	1400
July	1st to 10th	Night	29% 5% 19% 30% 15% 1	3270
	11th to 20th	Night	26% 5% 14% 35% 18% 2	3572
	21st to end	Night	30% 5% 16% 32% 15% 2	4182
August	1st to 10th	Night	36% 3 13% 29% 17% 3	2916
	11th to 20th	Night	33% 4 17% 31% 14% 1	2915
	21st to end	Night	31% 5% 16% 30% 16% 2	3360
September	1st to 10th	Night	28% 3 12% 35% 21% 1	2000
	11th to 20th	Night	29% 2 15% 34% 17% 1	2110
	21st to end	Night	32% 2 11% 33% 21% 2	2224
October	1st to 10th	Night	23% 1 6% 34% 31% 4	3920
	11th to 20th	Night	30% 2 12% 29% 23% 4	3899
	21st to end	Night	42% 2 11% 30% 14% 1	4252
November	1st to 10th	Night	41% 2 14% 26% 15% 2	2772
	11th to 20th	Night	49% 3 12% 22% 13% 1	2940
	21st to end	Night	47% 2 16% 24% 9% 1	2940
December	1st to 10th	Night	50% 3 18% 22% 7%	4720
	11th to 20th	Night	59% 3 13% 20% 4	5341
	21st to end	Night	72% 2 9% 14% 4	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	15% 12% 36% 25% 10% 2	330
	11th to 20th	Day	18% 12% 38% 27% 4	318
	21st to end	Day	14% 10% 37% 27% 12% 1	330
February	1st to 10th	Day	17% 15% 41% 22% 6%	300
	11th to 20th	Day	16% 14% 37% 30% 4	300
	21st to end	Day	21% 10% 42% 25% 2	249
March	1st to 10th	Day	18% 13% 43% 22% 3	300
	11th to 20th	Day	22% 9% 37% 23% 7% 1	300
	21st to end	Day	32% 10% 29% 20% 7% 2	330
April	1st to 10th	Day	28% 12% 31% 23% 6%	468
	11th to 20th	Day	29% 12% 27% 24% 7% 1	562
	21st to end	Day	28% 13% 27% 22% 8% 2	700
May	1st to 10th	Day	22% 9% 33% 22% 11% 2	703
	11th to 20th	Day	22% 10% 27% 25% 13% 3	725
	21st to end	Day	18% 6% 29% 31% 14% 2	789
June	1st to 10th	Day	12% 8% 24% 32% 18% 5%	730
	11th to 20th	Day	16% 9% 32% 29% 11% 2	730
	21st to end	Day	13% 7% 32% 30% 15% 4	730
July	1st to 10th	Day	9% 4 20% 33% 26% 9%	721
	11th to 20th	Day	9% 4 24% 33% 22% 7%	718
	21st to end	Day	8% 3 22% 40% 21% 6%	794
August	1st to 10th	Day	11% 3 20% 33% 26% 7%	726
	11th to 20th	Day	14% 4 19% 30% 28% 6%	715
	21st to end	Day	10% 4 25% 33% 21% 6%	724
September	1st to 10th	Day	16% 6% 25% 31% 18% 4	530
	11th to 20th	Day	10% 5% 31% 30% 19% 5%	415
	21st to end	Day	14% 11% 28% 25% 15% 7%	330
October	1st to 10th	Day	18% 12% 29% 25% 12% 4	330
	11th to 20th	Day	20% 16% 39% 19% 5% 1	330
	21st to end	Day	26% 12% 39% 17% 6% 1	363
November	1st to 10th	Day	22% 12% 35% 22% 8% 2	330
	11th to 20th	Day	20% 17% 40% 18% 6%	330
	21st to end	Day	21% 16% 35% 22% 6%	330
December	1st to 10th	Day	15% 10% 44% 25% 5%	330
	11th to 20th	Day	19% 13% 40% 24% 4	330
	21st to end	Day	27% 15% 35% 20% 4	363
January	1st to 10th	Night	12% 11% 38% 30% 9% 1	1050
	11th to 20th	Night	16% 10% 35% 31% 6% 1	1031
	21st to end	Night	18% 11% 34% 29% 7%	1100
February	1st to 10th	Night	16% 12% 38% 28% 6% 1	1000
	11th to 20th	Night	14% 13% 39% 27% 7% 1	979
	21st to end	Night	14% 11% 34% 31% 9% 1	797
March	1st to 10th	Night	16% 9% 39% 27% 8% 1	600
	11th to 20th	Night	20% 9% 37% 27% 8%	600
	21st to end	Night	25% 8% 29% 27% 8% 2	660
April	1st to 10th	Night	19% 11% 38% 28% 5%	600
	11th to 20th	Night	25% 11% 29% 26% 8% 1	593
	21st to end	Night	24% 9% 32% 27% 8% 1	600
May	1st to 10th	Night	19% 8% 31% 32% 10% 1	600
	11th to 20th	Night	21% 6% 30% 30% 11% 1	591
	21st to end	Night	19% 4 26% 37% 13% 1	650
June	1st to 10th	Night	12% 4 29% 41% 14% 1	600
	11th to 20th	Night	13% 3 32% 41% 10%	600
	21st to end	Night	10% 5% 26% 45% 14% 1	600
July	1st to 10th	Night	5% 4 20% 41% 27% 3	585
	11th to 20th	Night	4 2 24% 46% 23% 1	582
	21st to end	Night	5% 1 22% 49% 21% 2	657
August	1st to 10th	Night	9% 2 18% 45% 25% 2	597
	11th to 20th	Night	10% 2 16% 43% 25% 4	594
	21st to end	Night	7% 2 23% 43% 22% 2	660
September	1st to 10th	Night	12% 3 23% 41% 19% 2	600
	11th to 20th	Night	12% 3 30% 35% 19% 2	600
	21st to end	Night	13% 7% 31% 32% 16% 1	624
October	1st to 10th	Night	16% 8% 33% 30% 13% 1	800
	11th to 20th	Night	20% 9% 36% 27% 7% 1	800
	21st to end	Night	23% 11% 31% 29% 7%	880
November	1st to 10th	Night	17% 11% 34% 29% 8% 1	991
	11th to 20th	Night	19% 11% 38% 26% 6%	1050
	21st to end	Night	18% 11% 37% 27% 7%	1050
December	1st to 10th	Night	16% 10% 35% 31% 8% 1	1050
	11th to 20th	Night	21% 9% 34% 28% 7% 1	1050
	21st to end	Night	25% 10% 32% 28% 5%	1155

Page generated at 2026-01-14 00:14:27. Version ac07

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