Owatonna
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Owatonna clear sky chart from 2005-11-06 to 2024-11-25.

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% 9% 3 8% 5% 4 4 4 6% 7% 37%	101716
	Night	12% 9% 4 8% 5% 4 4 4 5% 6% 39%	97850
Transparency	Day	46% 4 13% 25% 11% 1	105336
	Night	45% 3 12% 24% 14% 2	102370
Seeing	Day	17% 9% 31% 27% 13% 3	16043
	Night	16% 9% 34% 30% 10% 1	25931

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% 17% 7% 20% 8% 7% 6% 4 4 5% 15%	2527
	11th to 20th	Day	6% 14% 4 12% 9% 8% 9% 5% 10% 7% 16%	2608
	21st to end	Day	9% 18% 9% 17% 8% 5% 5% 3 5% 5% 16%	3135
February	1st to 10th	Day	8% 12% 6% 12% 8% 7% 6% 6% 6% 6% 24%	1710
	11th to 20th	Day	10% 11% 5% 10% 6% 6% 7% 5% 5% 6% 30%	1664
	21st to end	Day	14% 9% 4 10% 7% 6% 5% 4 6% 7% 28%	1484
March	1st to 10th	Day	14% 8% 3 7% 4 3 4 3 6% 7% 40%	3375
	11th to 20th	Day	11% 10% 3 8% 4 4 4 4 5% 8% 40%	3480
	21st to end	Day	24% 13% 5% 12% 6% 4 4 3 4 4 21%	3845
April	1st to 10th	Day	18% 12% 4 7% 4 5% 4 3 7% 6% 30%	2280
	11th to 20th	Day	19% 13% 4 7% 4 3 4 3 4 6% 32%	2254
	21st to end	Day	21% 11% 4 8% 5% 4 4 3 5% 5% 29%	2456
May	1st to 10th	Day	17% 7% 2 6% 5% 4 4 4 6% 8% 36%	4206
	11th to 20th	Day	13% 6% 2 7% 4 4 4 4 5% 8% 43%	4399
	21st to end	Day	18% 8% 2 6% 4 4 4 4 5% 7% 38%	4824
June	1st to 10th	Day	12% 5% 2 6% 5% 3 5% 3 5% 8% 46%	2660
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 4 7% 9% 39%	2660
	21st to end	Day	12% 5% 2 6% 5% 5% 5% 4 7% 9% 40%	2660
July	1st to 10th	Day	11% 5% 3 7% 5% 5% 6% 5% 7% 10% 38%	4440
	11th to 20th	Day	6% 3 2 5% 3 4 3 4 6% 8% 57%	4440
	21st to end	Day	6% 4 2 6% 5% 5% 5% 4 8% 9% 46%	4693
August	1st to 10th	Day	12% 7% 2 6% 4 5% 4 4 7% 7% 43%	4104
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 4 6% 8% 41%	4041
	21st to end	Day	7% 5% 3 6% 4 5% 5% 4 5% 8% 48%	4308
September	1st to 10th	Day	13% 5% 2 5% 4 4 4 4 5% 7% 47%	2280
	11th to 20th	Day	11% 6% 3 5% 3 3 5% 2 5% 8% 48%	2252
	21st to end	Day	13% 7% 2 6% 4 3 4 3 6% 7% 45%	1998
October	1st to 10th	Day	16% 7% 2 5% 5% 4 3 3 5% 5% 45%	1900
	11th to 20th	Day	15% 11% 2 6% 3 4 4 3 5% 6% 42%	1900
	21st to end	Day	18% 12% 3 7% 4 3 3 3 5% 6% 36%	2087
November	1st to 10th	Day	12% 11% 3 7% 4 4 4 3 6% 7% 39%	1673
	11th to 20th	Day	11% 14% 6% 10% 6% 4 4 4 5% 5% 30%	1600
	21st to end	Day	12% 13% 4 7% 7% 4 3 3 4 8% 35%	1552
December	1st to 10th	Day	13% 11% 4 13% 9% 7% 5% 3 4 6% 25%	1520
	11th to 20th	Day	10% 14% 5% 11% 6% 6% 5% 5% 6% 7% 26%	1918
	21st to end	Day	18% 17% 7% 19% 5% 5% 3 2 4 5% 16%	2783
January	1st to 10th	Night	9% 15% 7% 20% 6% 4 5% 4 4 5% 22%	4428
	11th to 20th	Night	7% 12% 5% 14% 8% 7% 7% 7% 9% 5% 19%	4348
	21st to end	Night	12% 16% 8% 14% 6% 5% 4 4 4 5% 22%	4532
February	1st to 10th	Night	7% 14% 6% 11% 7% 6% 5% 4 5% 6% 32%	2470
	11th to 20th	Night	8% 10% 4 8% 6% 6% 5% 4 6% 7% 36%	2403
	21st to end	Night	12% 10% 3 10% 5% 5% 5% 3 5% 6% 35%	1970
March	1st to 10th	Night	11% 8% 3 6% 4 3 4 4 4 7% 46%	3497
	11th to 20th	Night	10% 7% 3 7% 5% 5% 4 3 5% 9% 42%	3480
	21st to end	Night	24% 13% 4 10% 4 3 3 3 4 5% 29%	3786
April	1st to 10th	Night	15% 11% 3 8% 4 4 4 4 6% 5% 37%	1900
	11th to 20th	Night	19% 11% 3 7% 5% 4 3 3 5% 5% 35%	1875
	21st to end	Night	19% 11% 3 7% 4 3 3 3 5% 5% 37%	1722
May	1st to 10th	Night	15% 7% 3 7% 4 4 4 3 4 6% 43%	2696
	11th to 20th	Night	13% 5% 2 5% 3 4 4 3 5% 7% 49%	2506
	21st to end	Night	13% 7% 3 6% 4 4 5% 3 5% 6% 43%	2743
June	1st to 10th	Night	10% 4 2 6% 4 4 4 4 5% 8% 49%	1520
	11th to 20th	Night	11% 4 2 6% 5% 4 4 4 7% 9% 43%	1520
	21st to end	Night	10% 5% 1 4 3 3 4 3 6% 8% 55%	1520
July	1st to 10th	Night	10% 4 2 5% 4 4 5% 5% 7% 9% 46%	2530
	11th to 20th	Night	3 3 2 4 4 4 3 3 6% 8% 61%	2530
	21st to end	Night	5% 3 2 4 3 4 4 4 6% 8% 57%	2867
August	1st to 10th	Night	12% 6% 2 6% 4 3 4 3 5% 6% 47%	2836
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 5% 8% 51%	2798
	21st to end	Night	9% 5% 2 6% 4 3 4 4 5% 7% 52%	3352
September	1st to 10th	Night	10% 4 2 5% 3 3 3 3 4 6% 57%	1900
	11th to 20th	Night	11% 5% 2 5% 3 3 3 3 4 8% 53%	1924
	21st to end	Night	11% 6% 2 5% 3 3 3 2 4 7% 53%	2161
October	1st to 10th	Night	13% 6% 2 5% 3 3 3 4 4 6% 50%	2280
	11th to 20th	Night	15% 8% 2 5% 3 4 4 3 5% 7% 43%	2280
	21st to end	Night	18% 10% 3 7% 3 3 4 3 6% 6% 38%	2509
November	1st to 10th	Night	12% 9% 3 6% 4 3 4 3 5% 6% 44%	2621
	11th to 20th	Night	11% 13% 5% 10% 5% 4 3 3 5% 5% 36%	2800
	21st to end	Night	13% 12% 4 8% 5% 4 3 2 4 6% 37%	2723
December	1st to 10th	Night	9% 12% 5% 11% 8% 5% 4 5% 6% 7% 29%	2660
	11th to 20th	Night	11% 12% 4 12% 7% 6% 4 4 5% 6% 27%	3279
	21st to end	Night	20% 15% 5% 15% 7% 5% 3 3 5% 5% 18%	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	71% 4 9% 13% 4	2528
	11th to 20th	Day	62% 3 11% 17% 8%	2608
	21st to end	Day	70% 4 11% 11% 4	3135
February	1st to 10th	Day	59% 4 11% 16% 9% 1	1710
	11th to 20th	Day	53% 4 11% 23% 7% 2	1673
	21st to end	Day	54% 4 12% 19% 10% 1	1484
March	1st to 10th	Day	43% 4 13% 26% 13% 1	3375
	11th to 20th	Day	43% 4 9% 31% 11% 2	3480
	21st to end	Day	68% 2 9% 15% 5%	3845
April	1st to 10th	Day	53% 4 11% 21% 9% 1	2280
	11th to 20th	Day	54% 3 11% 19% 12% 1	2254
	21st to end	Day	57% 4 11% 19% 8% 1	2456
May	1st to 10th	Day	45% 5% 13% 25% 11% 1	4244
	11th to 20th	Day	39% 5% 11% 31% 12% 2	4403
	21st to end	Day	46% 5% 12% 26% 11% 1	4837
June	1st to 10th	Day	36% 5% 15% 30% 14% 1	2660
	11th to 20th	Day	41% 4 15% 23% 16% 1	2660
	21st to end	Day	39% 5% 18% 26% 11% 2	2660
July	1st to 10th	Day	42% 3 20% 25% 9% 1	4371
	11th to 20th	Day	26% 3 15% 36% 18% 2	4365
	21st to end	Day	32% 5% 16% 29% 15% 2	4545
August	1st to 10th	Day	39% 4 13% 31% 12% 2	4090
	11th to 20th	Day	40% 4 15% 30% 10%	4080
	21st to end	Day	34% 4 17% 28% 15% 1	4307
September	1st to 10th	Day	36% 4 12% 32% 16%	2280
	11th to 20th	Day	35% 4 16% 32% 12% 1	2252
	21st to end	Day	40% 4 11% 31% 14% 1	1998
October	1st to 10th	Day	29% 3 7% 37% 23% 1	3160
	11th to 20th	Day	40% 2 13% 23% 22% 1	3140
	21st to end	Day	43% 2 13% 32% 10%	3413
November	1st to 10th	Day	44% 4 14% 20% 15% 3	1673
	11th to 20th	Day	56% 4 11% 19% 10% 1	1600
	21st to end	Day	50% 4 17% 21% 8% 1	1552
December	1st to 10th	Day	60% 4 16% 12% 7% 1	1520
	11th to 20th	Day	57% 3 19% 15% 6%	1915
	21st to end	Day	72% 3 9% 12% 4 1	2783
January	1st to 10th	Night	65% 4 9% 16% 6%	4428
	11th to 20th	Night	60% 4 11% 18% 6%	4348
	21st to end	Night	65% 3 10% 15% 6%	4532
February	1st to 10th	Night	55% 2 10% 22% 9% 1	2470
	11th to 20th	Night	47% 4 12% 25% 10% 2	2404
	21st to end	Night	50% 3 11% 22% 12% 2	1970
March	1st to 10th	Night	39% 3 11% 30% 16% 1	3497
	11th to 20th	Night	40% 4 8% 30% 18% 1	3480
	21st to end	Night	60% 3 9% 18% 8% 2	3786
April	1st to 10th	Night	48% 4 10% 23% 14% 1	1900
	11th to 20th	Night	51% 4 10% 17% 15% 3	1875
	21st to end	Night	49% 3 9% 23% 14% 2	1722
May	1st to 10th	Night	42% 4 11% 19% 22% 1	2723
	11th to 20th	Night	35% 4 11% 27% 18% 5%	2507
	21st to end	Night	41% 3 11% 27% 17% 1	2751
June	1st to 10th	Night	32% 5% 13% 32% 16% 2	1520
	11th to 20th	Night	37% 5% 14% 22% 18% 3	1520
	21st to end	Night	29% 3 17% 30% 19% 2	1520
July	1st to 10th	Night	35% 3 21% 28% 12% 1	2490
	11th to 20th	Night	22% 3 16% 38% 20% 2	2482
	21st to end	Night	24% 4 18% 31% 20% 2	2776
August	1st to 10th	Night	38% 3 12% 29% 16% 3	2826
	11th to 20th	Night	33% 3 16% 32% 16% 1	2825
	21st to end	Night	33% 3 18% 27% 17% 2	3352
September	1st to 10th	Night	28% 4 12% 33% 22% 1	1900
	11th to 20th	Night	32% 2 16% 32% 17% 1	1924
	21st to end	Night	33% 2 12% 32% 19% 1	2161
October	1st to 10th	Night	25% 2 6% 34% 29% 4	3800
	11th to 20th	Night	29% 3 14% 27% 23% 4	3779
	21st to end	Night	45% 2 11% 27% 14% 1	4133
November	1st to 10th	Night	41% 3 14% 25% 15% 2	2621
	11th to 20th	Night	51% 3 12% 19% 13% 1	2800
	21st to end	Night	49% 3 15% 23% 9% 1	2723
December	1st to 10th	Night	54% 4 16% 18% 7% 1	2660
	11th to 20th	Night	57% 4 14% 18% 6% 1	3281
	21st to end	Night	69% 3 9% 14% 5%	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	16% 10% 40% 23% 9% 3	270
	11th to 20th	Day	17% 11% 43% 24% 3 1	270
	21st to end	Day	14% 9% 39% 27% 10% 1	297
February	1st to 10th	Day	11% 16% 44% 25% 3 1	270
	11th to 20th	Day	16% 13% 40% 26% 4 1	270
	21st to end	Day	23% 13% 38% 23% 4	225
March	1st to 10th	Day	15% 15% 43% 20% 6%	270
	11th to 20th	Day	20% 13% 35% 23% 7% 1	270
	21st to end	Day	31% 11% 28% 19% 10% 1	316
April	1st to 10th	Day	27% 12% 35% 20% 5%	460
	11th to 20th	Day	26% 18% 23% 25% 8% 1	452
	21st to end	Day	27% 13% 28% 19% 10% 3	636
May	1st to 10th	Day	22% 12% 33% 24% 7% 2	653
	11th to 20th	Day	21% 11% 28% 26% 11% 4	675
	21st to end	Day	20% 9% 28% 25% 15% 3	734
June	1st to 10th	Day	12% 8% 25% 31% 19% 5%	680
	11th to 20th	Day	15% 7% 31% 33% 11% 3	680
	21st to end	Day	15% 8% 31% 28% 14% 5%	680
July	1st to 10th	Day	7% 3 22% 35% 25% 9%	671
	11th to 20th	Day	7% 6% 29% 30% 21% 8%	668
	21st to end	Day	8% 2 23% 39% 22% 6%	739
August	1st to 10th	Day	10% 4 21% 35% 23% 6%	676
	11th to 20th	Day	15% 3 20% 32% 24% 6%	665
	21st to end	Day	10% 4 31% 31% 18% 6%	615
September	1st to 10th	Day	15% 6% 29% 31% 15% 4	490
	11th to 20th	Day	13% 6% 29% 33% 16% 3	462
	21st to end	Day	17% 11% 31% 25% 11% 5%	300
October	1st to 10th	Day	19% 10% 27% 25% 15% 4	300
	11th to 20th	Day	20% 14% 40% 19% 6% 1	300
	21st to end	Day	27% 16% 35% 14% 7% 1	330
November	1st to 10th	Day	18% 13% 36% 24% 9% 1	300
	11th to 20th	Day	19% 19% 42% 16% 4	300
	21st to end	Day	20% 12% 43% 22% 3	282
December	1st to 10th	Day	16% 10% 42% 25% 6% 1	270
	11th to 20th	Day	17% 14% 39% 23% 6% 1	270
	21st to end	Day	28% 14% 37% 17% 4	297
January	1st to 10th	Night	13% 11% 41% 27% 8%	950
	11th to 20th	Night	17% 12% 38% 27% 6% 1	950
	21st to end	Night	19% 11% 36% 28% 6%	1045
February	1st to 10th	Night	15% 11% 41% 27% 5% 1	950
	11th to 20th	Night	13% 14% 43% 23% 6% 1	929
	21st to end	Night	17% 12% 36% 27% 7% 1	714
March	1st to 10th	Night	18% 10% 40% 23% 8% 1	626
	11th to 20th	Night	19% 9% 36% 26% 8% 1	570
	21st to end	Night	24% 9% 30% 25% 10% 2	627
April	1st to 10th	Night	20% 14% 36% 25% 4	570
	11th to 20th	Night	24% 11% 32% 26% 6% 1	563
	21st to end	Night	25% 8% 32% 27% 7% 2	570
May	1st to 10th	Night	21% 9% 32% 30% 8% 1	570
	11th to 20th	Night	19% 7% 30% 33% 10% 1	561
	21st to end	Night	17% 7% 28% 35% 12% 1	617
June	1st to 10th	Night	11% 5% 29% 41% 14% 1	570
	11th to 20th	Night	14% 5% 31% 40% 10%	570
	21st to end	Night	11% 3 26% 42% 16% 1	570
July	1st to 10th	Night	8% 1 20% 41% 26% 3	555
	11th to 20th	Night	5% 4 25% 41% 24% 3	552
	21st to end	Night	5% 2 19% 50% 22% 3	624
August	1st to 10th	Night	9% 2 19% 44% 25% 2	567
	11th to 20th	Night	11% 2 21% 39% 22% 4	564
	21st to end	Night	8% 1 26% 41% 20% 3	627
September	1st to 10th	Night	12% 4 24% 40% 16% 4	570
	11th to 20th	Night	12% 4 31% 35% 16% 2	570
	21st to end	Night	14% 7% 32% 31% 15% 1	641
October	1st to 10th	Night	15% 9% 31% 29% 14% 1	760
	11th to 20th	Night	19% 10% 37% 27% 7% 1	760
	21st to end	Night	24% 11% 31% 27% 6%	836
November	1st to 10th	Night	18% 12% 37% 25% 7% 1	865
	11th to 20th	Night	18% 14% 41% 22% 6%	1000
	21st to end	Night	17% 14% 40% 22% 7%	973
December	1st to 10th	Night	15% 11% 40% 27% 6% 1	950
	11th to 20th	Night	19% 8% 42% 24% 7%	950
	21st to end	Night	24% 13% 35% 24% 5%	1045

Page generated at 2024-11-22 07:02:30. Version ac07

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