Fishers
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fishers 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	14% 9% 3 7% 5% 4 4 4 6% 7% 36%	101051
	Night	15% 10% 4 7% 4 4 4 3 5% 7% 37%	98029
Transparency	Day	45% 6% 12% 22% 13% 2	104692
	Night	45% 6% 11% 22% 15% 2	102528
Seeing	Day	17% 11% 26% 24% 16% 6%	15588
	Night	18% 9% 29% 29% 14% 1	25390

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	15% 17% 9% 10% 5% 5% 4 3 4 5% 23%	2527
	11th to 20th	Day	16% 14% 7% 13% 5% 6% 7% 6% 5% 4 16%	2530
	21st to end	Day	26% 21% 9% 11% 4 2 3 2 3 3 16%	2911
February	1st to 10th	Day	18% 13% 6% 9% 8% 5% 3 3 3 5% 25%	1885
	11th to 20th	Day	14% 12% 4 11% 6% 5% 4 3 4 5% 31%	1848
	21st to end	Day	17% 15% 5% 10% 5% 3 3 3 4 5% 31%	1570
March	1st to 10th	Day	20% 20% 4 8% 4 3 3 3 4 4 27%	3120
	11th to 20th	Day	13% 8% 3 7% 4 3 4 3 5% 7% 43%	3374
	21st to end	Day	16% 10% 4 9% 5% 5% 4 3 5% 6% 30%	3966
April	1st to 10th	Day	15% 11% 4 8% 6% 4 4 3 4 7% 34%	2280
	11th to 20th	Day	17% 9% 3 6% 5% 4 4 4 5% 7% 36%	2254
	21st to end	Day	19% 8% 3 8% 5% 4 4 3 4 7% 35%	2453
May	1st to 10th	Day	19% 10% 3 8% 5% 5% 5% 4 6% 8% 28%	4082
	11th to 20th	Day	19% 7% 2 6% 5% 4 4 3 5% 8% 37%	4081
	21st to end	Day	10% 6% 3 7% 5% 5% 5% 5% 7% 9% 38%	4567
June	1st to 10th	Day	11% 6% 2 6% 5% 5% 6% 4 6% 8% 40%	2660
	11th to 20th	Day	9% 5% 1 6% 4 4 5% 5% 7% 8% 45%	2660
	21st to end	Day	9% 6% 2 6% 6% 5% 6% 4 6% 9% 42%	2660
July	1st to 10th	Day	13% 7% 3 7% 5% 5% 5% 4 7% 10% 34%	4440
	11th to 20th	Day	6% 4 2 5% 4 4 5% 5% 7% 12% 45%	4440
	21st to end	Day	9% 6% 2 8% 5% 5% 6% 5% 7% 9% 37%	4666
August	1st to 10th	Day	8% 5% 2 5% 4 4 5% 4 7% 11% 45%	4104
	11th to 20th	Day	8% 6% 2 7% 4 5% 5% 4 7% 11% 42%	3894
	21st to end	Day	6% 4 2 6% 4 4 4 4 6% 9% 51%	4180
September	1st to 10th	Day	11% 7% 2 7% 4 4 4 3 6% 7% 45%	2242
	11th to 20th	Day	9% 5% 1 6% 4 4 4 4 6% 9% 47%	2090
	21st to end	Day	14% 6% 2 5% 4 4 4 3 4 7% 47%	2090
October	1st to 10th	Day	12% 5% 2 6% 4 4 4 3 5% 7% 48%	2090
	11th to 20th	Day	13% 7% 3 6% 3 4 4 4 5% 6% 44%	1938
	21st to end	Day	18% 9% 4 7% 4 4 4 4 6% 7% 34%	1881
November	1st to 10th	Day	9% 8% 2 5% 5% 4 3 3 5% 6% 51%	1708
	11th to 20th	Day	15% 11% 4 8% 5% 4 4 3 6% 7% 35%	1710
	21st to end	Day	19% 10% 4 8% 4 4 3 3 5% 5% 35%	1710
December	1st to 10th	Day	19% 15% 5% 10% 4 4 4 3 3 6% 27%	1710
	11th to 20th	Day	15% 17% 7% 11% 4 4 3 3 5% 5% 27%	1947
	21st to end	Day	21% 21% 9% 11% 5% 4 3 3 4 5% 15%	2783
January	1st to 10th	Night	18% 16% 8% 12% 4 4 3 3 4 5% 23%	4428
	11th to 20th	Night	15% 19% 7% 14% 6% 5% 5% 4 4 3 18%	4440
	21st to end	Night	26% 18% 7% 9% 4 3 3 2 3 4 21%	4748
February	1st to 10th	Night	19% 13% 4 9% 6% 4 3 3 5% 5% 28%	2290
	11th to 20th	Night	14% 12% 4 10% 6% 4 3 3 5% 6% 33%	2218
	21st to end	Night	18% 13% 4 10% 4 4 4 3 5% 5% 30%	1884
March	1st to 10th	Night	20% 13% 3 7% 4 3 3 3 4 5% 35%	3733
	11th to 20th	Night	12% 7% 2 6% 4 4 4 3 5% 6% 46%	3586
	21st to end	Night	17% 9% 3 8% 5% 3 4 3 5% 6% 37%	3694
April	1st to 10th	Night	14% 10% 2 7% 4 3 4 4 6% 8% 38%	1900
	11th to 20th	Night	18% 8% 2 6% 4 3 4 3 5% 7% 40%	1875
	21st to end	Night	17% 8% 3 7% 5% 5% 5% 4 6% 7% 35%	1725
May	1st to 10th	Night	17% 12% 4 8% 5% 5% 5% 3 6% 7% 27%	2813
	11th to 20th	Night	20% 6% 2 6% 4 3 3 3 5% 8% 39%	2812
	21st to end	Night	10% 5% 2 5% 5% 5% 5% 4 6% 10% 43%	2987
June	1st to 10th	Night	8% 6% 3 6% 4 5% 4 3 6% 7% 48%	1520
	11th to 20th	Night	9% 7% 2 6% 3 4 4 3 5% 10% 47%	1520
	21st to end	Night	6% 4 2 5% 5% 5% 4 5% 7% 11% 45%	1520
July	1st to 10th	Night	10% 5% 2 6% 4 4 4 4 6% 10% 46%	2530
	11th to 20th	Night	5% 4 2 4 3 4 4 4 5% 9% 56%	2530
	21st to end	Night	9% 6% 3 8% 4 5% 5% 4 6% 9% 41%	2893
August	1st to 10th	Night	10% 5% 2 6% 4 4 4 3 5% 9% 49%	2825
	11th to 20th	Night	7% 6% 2 7% 5% 5% 5% 4 6% 9% 44%	2931
	21st to end	Night	5% 4 2 6% 4 4 4 3 6% 8% 54%	3476
September	1st to 10th	Night	11% 6% 1 6% 4 3 4 3 5% 7% 49%	1917
	11th to 20th	Night	7% 4 1 5% 4 4 4 3 5% 8% 56%	2090
	21st to end	Night	12% 6% 2 5% 4 4 4 3 5% 6% 49%	2090
October	1st to 10th	Night	9% 4 2 6% 4 4 4 3 5% 7% 54%	2090
	11th to 20th	Night	18% 7% 2 5% 3 3 3 3 4 6% 46%	2238
	21st to end	Night	18% 7% 3 6% 4 4 4 4 4 6% 40%	2717
November	1st to 10th	Night	12% 7% 3 5% 3 3 4 3 5% 5% 49%	2470
	11th to 20th	Night	14% 9% 4 7% 4 4 4 3 5% 6% 39%	2470
	21st to end	Night	19% 12% 4 8% 5% 4 3 3 4 6% 32%	2470
December	1st to 10th	Night	18% 11% 6% 9% 6% 4 3 4 4 5% 29%	2470
	11th to 20th	Night	17% 14% 5% 9% 5% 3 3 3 4 5% 31%	3245
	21st to end	Night	23% 20% 6% 10% 5% 5% 4 3 4 4 16%	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	63% 4 9% 18% 6%	2528
	11th to 20th	Day	70% 6% 10% 10% 4	2530
	21st to end	Day	75% 3 7% 12% 3	2911
February	1st to 10th	Day	61% 5% 8% 15% 10% 1	1885
	11th to 20th	Day	56% 5% 10% 20% 9% 1	1858
	21st to end	Day	56% 5% 10% 20% 7% 2	1570
March	1st to 10th	Day	60% 5% 7% 18% 9% 1	3120
	11th to 20th	Day	41% 5% 11% 30% 12% 1	3374
	21st to end	Day	51% 8% 15% 21% 5%	3966
April	1st to 10th	Day	49% 7% 12% 19% 13% 1	2280
	11th to 20th	Day	46% 6% 12% 22% 10% 3	2254
	21st to end	Day	50% 6% 11% 21% 10% 3	2453
May	1st to 10th	Day	52% 9% 14% 20% 6%	4120
	11th to 20th	Day	45% 8% 13% 24% 9%	4085
	21st to end	Day	36% 11% 14% 20% 18% 1	4580
June	1st to 10th	Day	39% 7% 13% 22% 15% 3	2660
	11th to 20th	Day	34% 8% 12% 24% 20% 2	2660
	21st to end	Day	38% 7% 15% 19% 16% 4	2660
July	1st to 10th	Day	44% 6% 12% 21% 15% 2	4371
	11th to 20th	Day	30% 6% 16% 28% 18% 1	4365
	21st to end	Day	41% 8% 16% 17% 14% 3	4518
August	1st to 10th	Day	32% 6% 17% 29% 15% 1	4091
	11th to 20th	Day	35% 6% 13% 33% 13%	3933
	21st to end	Day	29% 6% 14% 30% 17% 4	4179
September	1st to 10th	Day	36% 7% 12% 23% 18% 4	2242
	11th to 20th	Day	32% 7% 13% 24% 21% 3	2090
	21st to end	Day	36% 5% 11% 25% 22% 1	2090
October	1st to 10th	Day	24% 4 9% 32% 30% 2	3480
	11th to 20th	Day	34% 4 9% 26% 25% 1	3193
	21st to end	Day	41% 4 10% 24% 20% 1	3081
November	1st to 10th	Day	34% 5% 13% 27% 17% 4	1708
	11th to 20th	Day	49% 5% 9% 20% 13% 3	1710
	21st to end	Day	52% 4 11% 22% 10% 2	1710
December	1st to 10th	Day	60% 5% 10% 17% 8%	1710
	11th to 20th	Day	59% 5% 9% 21% 5% 1	1944
	21st to end	Day	73% 5% 8% 9% 5%	2783
January	1st to 10th	Night	63% 6% 10% 15% 6%	4428
	11th to 20th	Night	70% 5% 8% 12% 5%	4440
	21st to end	Night	68% 4 8% 13% 6%	4748
February	1st to 10th	Night	59% 4 12% 15% 8% 1	2290
	11th to 20th	Night	52% 5% 11% 18% 12% 1	2219
	21st to end	Night	56% 5% 11% 16% 10% 2	1884
March	1st to 10th	Night	52% 6% 9% 23% 10% 2	3733
	11th to 20th	Night	37% 7% 12% 24% 18% 2	3586
	21st to end	Night	47% 7% 11% 27% 7% 1	3694
April	1st to 10th	Night	43% 6% 13% 22% 14% 2	1900
	11th to 20th	Night	44% 5% 10% 20% 17% 5%	1875
	21st to end	Night	46% 8% 10% 20% 12% 4	1725
May	1st to 10th	Night	53% 9% 10% 19% 7% 1	2840
	11th to 20th	Night	42% 7% 14% 25% 10% 1	2813
	21st to end	Night	32% 10% 16% 23% 16% 3	2995
June	1st to 10th	Night	34% 6% 11% 25% 20% 3	1520
	11th to 20th	Night	34% 6% 11% 23% 21% 4	1520
	21st to end	Night	31% 9% 16% 23% 16% 4	1520
July	1st to 10th	Night	35% 6% 11% 27% 16% 5%	2490
	11th to 20th	Night	25% 5% 14% 32% 23% 2	2482
	21st to end	Night	39% 6% 15% 21% 15% 4	2801
August	1st to 10th	Night	33% 6% 14% 32% 14% 1	2814
	11th to 20th	Night	36% 6% 13% 27% 17% 1	2958
	21st to end	Night	28% 5% 13% 29% 22% 3	3476
September	1st to 10th	Night	33% 8% 12% 21% 20% 6%	1917
	11th to 20th	Night	27% 6% 11% 27% 26% 4	2090
	21st to end	Night	35% 6% 11% 23% 22% 3	2090
October	1st to 10th	Night	21% 4 7% 27% 39% 2	3480
	11th to 20th	Night	29% 3 9% 24% 33% 1	3722
	21st to end	Night	34% 3 8% 26% 24% 4	4467
November	1st to 10th	Night	36% 5% 11% 24% 22% 3	2470
	11th to 20th	Night	44% 5% 10% 22% 16% 3	2470
	21st to end	Night	54% 4 9% 22% 10%	2470
December	1st to 10th	Night	57% 4 11% 19% 9%	2470
	11th to 20th	Night	55% 4 9% 20% 11% 1	3247
	21st to end	Night	71% 5% 9% 10% 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	24% 20% 31% 21% 3	270
	11th to 20th	Day	23% 20% 37% 14% 6%	270
	21st to end	Day	31% 18% 28% 19% 4	297
February	1st to 10th	Day	29% 16% 33% 18% 4	270
	11th to 20th	Day	21% 23% 34% 16% 6%	270
	21st to end	Day	26% 18% 40% 14% 1	225
March	1st to 10th	Day	23% 26% 31% 17% 2	270
	11th to 20th	Day	26% 17% 33% 16% 7% 1	393
	21st to end	Day	30% 15% 32% 17% 6% 1	506
April	1st to 10th	Day	15% 21% 35% 19% 8% 2	460
	11th to 20th	Day	20% 18% 27% 21% 11% 2	452
	21st to end	Day	23% 17% 33% 18% 6% 2	460
May	1st to 10th	Day	22% 14% 31% 23% 8% 2	463
	11th to 20th	Day	23% 7% 28% 23% 13% 7%	487
	21st to end	Day	12% 7% 27% 24% 20% 10%	581
June	1st to 10th	Day	11% 7% 30% 28% 18% 6%	680
	11th to 20th	Day	11% 5% 24% 34% 19% 6%	680
	21st to end	Day	13% 7% 27% 29% 18% 7%	680
July	1st to 10th	Day	13% 2 17% 27% 25% 15%	671
	11th to 20th	Day	6% 5% 20% 34% 23% 12%	668
	21st to end	Day	10% 2 16% 32% 29% 11%	654
August	1st to 10th	Day	10% 4 14% 27% 30% 15%	486
	11th to 20th	Day	12% 4 19% 30% 24% 12%	479
	21st to end	Day	7% 3 13% 31% 31% 15%	539
September	1st to 10th	Day	12% 4 15% 31% 28% 10%	490
	11th to 20th	Day	9% 3 14% 28% 29% 17%	490
	21st to end	Day	17% 9% 22% 22% 21% 10%	490
October	1st to 10th	Day	10% 9% 23% 33% 18% 7%	490
	11th to 20th	Day	14% 17% 31% 23% 12% 3	428
	21st to end	Day	25% 17% 34% 19% 5%	330
November	1st to 10th	Day	11% 20% 30% 22% 15% 2	282
	11th to 20th	Day	21% 20% 30% 17% 9% 2	270
	21st to end	Day	25% 12% 37% 22% 4	270
December	1st to 10th	Day	20% 25% 33% 16% 4 1	270
	11th to 20th	Day	21% 19% 35% 18% 6% 1	270
	21st to end	Day	29% 21% 31% 16% 4	297
January	1st to 10th	Night	25% 16% 33% 22% 4	950
	11th to 20th	Night	27% 14% 37% 19% 4	950
	21st to end	Night	25% 15% 33% 24% 3	961
February	1st to 10th	Night	27% 12% 34% 25% 2	760
	11th to 20th	Night	20% 15% 38% 24% 3	743
	21st to end	Night	27% 12% 39% 21% 2	628
March	1st to 10th	Night	20% 16% 34% 24% 6%	760
	11th to 20th	Night	19% 14% 38% 23% 6% 1	760
	21st to end	Night	25% 11% 32% 27% 5% 1	764
April	1st to 10th	Night	18% 13% 36% 26% 7% 1	570
	11th to 20th	Night	19% 12% 31% 29% 9% 1	563
	21st to end	Night	22% 9% 40% 22% 7% 1	570
May	1st to 10th	Night	19% 10% 35% 27% 10%	570
	11th to 20th	Night	20% 5% 24% 32% 18% 1	561
	21st to end	Night	10% 4 25% 38% 22% 2	617
June	1st to 10th	Night	11% 4 25% 44% 15% 1	570
	11th to 20th	Night	11% 4 23% 40% 21% 1	570
	21st to end	Night	7% 3 24% 40% 24% 1	570
July	1st to 10th	Night	10% 2 14% 36% 32% 6%	555
	11th to 20th	Night	7% 3 17% 38% 31% 4	552
	21st to end	Night	8% 2 15% 42% 31% 2	624
August	1st to 10th	Night	9% 1 13% 40% 33% 4	567
	11th to 20th	Night	7% 2 13% 42% 30% 5%	564
	21st to end	Night	7% 1 15% 34% 38% 5%	627
September	1st to 10th	Night	13% 4 14% 34% 30% 5%	587
	11th to 20th	Night	8% 3 16% 34% 35% 4	760
	21st to end	Night	15% 5% 21% 32% 24% 2	760
October	1st to 10th	Night	11% 5% 24% 35% 20% 5%	760
	11th to 20th	Night	20% 10% 29% 26% 14%	760
	21st to end	Night	22% 10% 36% 25% 7%	836
November	1st to 10th	Night	16% 9% 34% 27% 13% 1	760
	11th to 20th	Night	17% 16% 31% 27% 8% 1	760
	21st to end	Night	26% 12% 28% 27% 7%	760
December	1st to 10th	Night	23% 13% 36% 23% 5%	760
	11th to 20th	Night	25% 11% 34% 23% 6%	916
	21st to end	Night	30% 15% 32% 19% 4	1045

Page generated at 2024-11-03 02:11:23. Version ac07

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