Fenelon Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fenelon Falls clear sky chart from 2005-11-06 to 2024-11-04.

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% 10% 4 8% 5% 5% 5% 4 5% 7% 33%	101519
	Night	16% 12% 4 9% 5% 4 4 3 5% 6% 31%	97412
Transparency	Day	49% 6% 12% 21% 10% 1	105118
	Night	50% 7% 12% 20% 10% 1	101901
Seeing	Day	22% 14% 31% 20% 10% 4	14408
	Night	21% 15% 30% 24% 10% 1	23690

By Month

Percentage Cloud Cover NE (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% 17% 7% 13% 6% 4 4 3 3 3 24%	2517
	11th to 20th	Day	10% 18% 7% 17% 8% 6% 5% 3 4 5% 17%	2620
	21st to end	Day	18% 21% 7% 12% 6% 5% 3 3 3 4 18%	3124
February	1st to 10th	Day	14% 16% 5% 15% 9% 4 5% 4 3 4 21%	1710
	11th to 20th	Day	13% 16% 6% 12% 6% 5% 6% 2 4 4 26%	1663
	21st to end	Day	17% 15% 6% 11% 6% 5% 4 3 4 5% 23%	1454
March	1st to 10th	Day	19% 13% 5% 9% 6% 4 5% 3 4 5% 28%	3417
	11th to 20th	Day	10% 16% 6% 11% 6% 5% 5% 4 5% 5% 27%	3480
	21st to end	Day	15% 10% 3 7% 4 4 5% 3 4 5% 41%	3815
April	1st to 10th	Day	19% 12% 4 8% 6% 4 4 3 5% 5% 30%	2280
	11th to 20th	Day	20% 11% 2 6% 5% 4 3 3 4 6% 36%	2300
	21st to end	Day	20% 10% 3 7% 5% 4 4 3 4 6% 34%	2470
May	1st to 10th	Day	18% 7% 3 7% 5% 5% 5% 4 6% 7% 34%	4204
	11th to 20th	Day	15% 11% 3 7% 5% 4 5% 4 5% 9% 34%	4398
	21st to end	Day	14% 7% 2 7% 4 4 4 4 5% 7% 43%	4837
June	1st to 10th	Day	18% 8% 2 7% 5% 4 4 4 6% 8% 35%	2660
	11th to 20th	Day	14% 6% 3 6% 4 5% 4 4 7% 9% 38%	2660
	21st to end	Day	17% 7% 2 7% 4 4 5% 3 6% 8% 37%	2660
July	1st to 10th	Day	11% 5% 2 6% 4 5% 6% 5% 7% 11% 38%	4440
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 4 7% 8% 44%	4440
	21st to end	Day	8% 6% 2 6% 5% 5% 6% 5% 8% 8% 43%	4667
August	1st to 10th	Day	15% 8% 3 6% 4 5% 4 4 6% 9% 36%	4104
	11th to 20th	Day	14% 7% 2 7% 5% 5% 5% 4 7% 10% 35%	4044
	21st to end	Day	8% 6% 2 6% 5% 4 5% 4 7% 9% 43%	4321
September	1st to 10th	Day	13% 7% 2 6% 5% 5% 5% 4 6% 7% 40%	2280
	11th to 20th	Day	12% 5% 1 6% 4 5% 4 3 6% 8% 46%	2219
	21st to end	Day	16% 6% 3 7% 5% 5% 5% 4 5% 6% 38%	2019
October	1st to 10th	Day	18% 10% 3 8% 5% 5% 4 3 5% 6% 33%	1900
	11th to 20th	Day	23% 10% 4 9% 5% 4 4 4 5% 6% 26%	1900
	21st to end	Day	25% 13% 4 8% 4 4 4 3 6% 6% 23%	2090
November	1st to 10th	Day	16% 11% 4 8% 5% 5% 4 4 5% 7% 31%	1588
	11th to 20th	Day	17% 12% 4 11% 6% 5% 4 4 7% 8% 23%	1520
	21st to end	Day	21% 18% 4 9% 6% 4 5% 4 5% 6% 19%	1520
December	1st to 10th	Day	17% 22% 7% 14% 6% 5% 4 3 3 5% 15%	1520
	11th to 20th	Day	18% 16% 5% 10% 6% 4 5% 3 4 5% 24%	1906
	21st to end	Day	26% 18% 6% 12% 5% 4 4 2 4 4 15%	2772
January	1st to 10th	Night	17% 19% 7% 13% 7% 6% 4 3 4 4 15%	4429
	11th to 20th	Night	13% 13% 7% 16% 9% 6% 6% 4 5% 5% 17%	4339
	21st to end	Night	18% 16% 8% 11% 6% 5% 5% 3 5% 5% 19%	4532
February	1st to 10th	Night	13% 16% 5% 12% 8% 7% 5% 4 5% 5% 20%	2470
	11th to 20th	Night	12% 15% 5% 11% 6% 5% 5% 4 6% 5% 26%	2403
	21st to end	Night	14% 14% 5% 11% 6% 4 5% 3 6% 6% 26%	1999
March	1st to 10th	Night	17% 11% 5% 10% 5% 5% 4 3 5% 6% 30%	3422
	11th to 20th	Night	12% 16% 6% 9% 6% 4 5% 3 5% 6% 28%	3479
	21st to end	Night	15% 8% 4 7% 4 4 4 4 6% 7% 38%	3817
April	1st to 10th	Night	19% 13% 4 7% 5% 4 4 3 4 6% 30%	1900
	11th to 20th	Night	17% 9% 3 7% 4 3 3 3 5% 7% 37%	1845
	21st to end	Night	16% 11% 3 8% 5% 4 3 4 6% 6% 33%	1710
May	1st to 10th	Night	18% 8% 3 7% 5% 4 4 3 5% 6% 37%	2721
	11th to 20th	Night	14% 8% 3 6% 5% 5% 4 4 5% 7% 38%	2495
	21st to end	Night	11% 7% 3 6% 4 4 4 3 5% 7% 47%	2738
June	1st to 10th	Night	16% 6% 2 6% 5% 5% 5% 4 6% 8% 37%	1520
	11th to 20th	Night	11% 6% 2 5% 5% 5% 4 4 6% 9% 44%	1520
	21st to end	Night	13% 9% 2 7% 6% 5% 4 4 6% 9% 37%	1442
July	1st to 10th	Night	8% 5% 2 6% 6% 5% 5% 4 6% 8% 45%	2520
	11th to 20th	Night	13% 6% 2 4 4 4 4 3 5% 8% 48%	2520
	21st to end	Night	8% 6% 2 4 3 4 5% 3 6% 9% 49%	2883
August	1st to 10th	Night	11% 5% 2 6% 5% 4 4 4 5% 8% 46%	2825
	11th to 20th	Night	14% 6% 2 5% 4 3 4 4 5% 6% 46%	2785
	21st to end	Night	11% 6% 2 5% 4 4 4 3 6% 7% 46%	3302
September	1st to 10th	Night	11% 6% 2 6% 4 4 5% 4 6% 8% 44%	1900
	11th to 20th	Night	12% 5% 2 5% 4 3 2 4 4 7% 51%	1957
	21st to end	Night	16% 8% 3 6% 4 4 4 3 5% 7% 40%	2160
October	1st to 10th	Night	17% 8% 3 8% 5% 5% 4 3 6% 6% 35%	2280
	11th to 20th	Night	20% 11% 3 9% 5% 4 5% 4 5% 5% 29%	2280
	21st to end	Night	23% 13% 2 8% 5% 5% 5% 3 4 6% 25%	2508
November	1st to 10th	Night	18% 12% 4 7% 5% 4 4 3 5% 7% 33%	2559
	11th to 20th	Night	17% 14% 4 9% 5% 5% 4 4 5% 7% 26%	2660
	21st to end	Night	21% 14% 3 11% 6% 6% 5% 5% 5% 6% 19%	2660
December	1st to 10th	Night	19% 18% 6% 13% 6% 4 4 3 4 5% 16%	2660
	11th to 20th	Night	17% 19% 6% 12% 6% 5% 4 3 4 5% 19%	3288
	21st to end	Night	27% 20% 7% 13% 5% 4 3 2 3 4 12%	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	62% 7% 12% 11% 8%	2518
	11th to 20th	Day	70% 6% 9% 9% 6%	2620
	21st to end	Day	71% 5% 8% 10% 6% 1	3124
February	1st to 10th	Day	67% 5% 8% 15% 4 1	1710
	11th to 20th	Day	61% 5% 9% 14% 9% 1	1672
	21st to end	Day	62% 5% 9% 15% 8% 1	1454
March	1st to 10th	Day	56% 6% 13% 14% 10% 1	3420
	11th to 20th	Day	55% 7% 11% 17% 8% 1	3480
	21st to end	Day	43% 6% 9% 23% 17% 2	3815
April	1st to 10th	Day	56% 4 9% 19% 11% 2	2280
	11th to 20th	Day	50% 5% 8% 22% 15% 1	2300
	21st to end	Day	52% 5% 10% 19% 13% 3	2470
May	1st to 10th	Day	48% 6% 11% 21% 12% 1	4216
	11th to 20th	Day	46% 7% 13% 21% 11%	4402
	21st to end	Day	39% 6% 13% 23% 16% 3	4837
June	1st to 10th	Day	47% 7% 10% 20% 15%	2660
	11th to 20th	Day	41% 6% 13% 24% 14% 1	2660
	21st to end	Day	43% 8% 13% 22% 12% 1	2660
July	1st to 10th	Day	38% 7% 17% 25% 13% 1	4370
	11th to 20th	Day	35% 6% 15% 34% 9% 1	4365
	21st to end	Day	35% 8% 12% 32% 13%	4518
August	1st to 10th	Day	44% 6% 15% 24% 10% 1	4091
	11th to 20th	Day	42% 7% 15% 26% 9%	4083
	21st to end	Day	36% 7% 13% 34% 11% 1	4321
September	1st to 10th	Day	41% 7% 14% 27% 10% 1	2280
	11th to 20th	Day	36% 6% 14% 30% 13% 1	2219
	21st to end	Day	46% 6% 13% 25% 10%	2019
October	1st to 10th	Day	43% 5% 13% 28% 10% 1	3160
	11th to 20th	Day	48% 6% 14% 21% 11% 1	3140
	21st to end	Day	54% 6% 14% 18% 7%	3428
November	1st to 10th	Day	50% 8% 15% 19% 8% 1	1588
	11th to 20th	Day	57% 8% 13% 14% 7% 2	1520
	21st to end	Day	64% 7% 11% 13% 5%	1520
December	1st to 10th	Day	72% 6% 9% 10% 3	1520
	11th to 20th	Day	62% 9% 9% 12% 7% 1	1906
	21st to end	Day	73% 4 8% 11% 3	2772
January	1st to 10th	Night	69% 7% 9% 10% 4	4429
	11th to 20th	Night	66% 9% 9% 11% 4 1	4339
	21st to end	Night	66% 6% 11% 10% 6% 1	4532
February	1st to 10th	Night	64% 6% 8% 16% 5% 1	2470
	11th to 20th	Night	57% 6% 11% 18% 8%	2405
	21st to end	Night	57% 6% 10% 19% 8% 1	1999
March	1st to 10th	Night	54% 6% 10% 19% 10% 1	3432
	11th to 20th	Night	54% 7% 15% 16% 7% 1	3480
	21st to end	Night	41% 8% 10% 24% 15% 2	3817
April	1st to 10th	Night	55% 5% 8% 20% 12% 2	1900
	11th to 20th	Night	47% 5% 9% 22% 16% 2	1845
	21st to end	Night	49% 6% 11% 17% 15% 2	1710
May	1st to 10th	Night	46% 6% 13% 17% 15% 2	2728
	11th to 20th	Night	43% 7% 14% 23% 11% 2	2496
	21st to end	Night	35% 7% 13% 26% 18% 2	2739
June	1st to 10th	Night	42% 7% 11% 23% 14% 2	1520
	11th to 20th	Night	36% 6% 12% 25% 20% 2	1520
	21st to end	Night	43% 7% 14% 21% 14% 1	1442
July	1st to 10th	Night	35% 6% 16% 24% 17% 2	2480
	11th to 20th	Night	34% 6% 13% 33% 14%	2472
	21st to end	Night	31% 7% 13% 34% 14% 1	2791
August	1st to 10th	Night	36% 6% 16% 25% 17% 1	2814
	11th to 20th	Night	36% 7% 17% 26% 13% 1	2812
	21st to end	Night	34% 7% 12% 34% 12% 1	3302
September	1st to 10th	Night	36% 7% 16% 27% 13% 1	1900
	11th to 20th	Night	32% 6% 13% 33% 15% 1	1957
	21st to end	Night	43% 6% 11% 29% 11%	2160
October	1st to 10th	Night	36% 6% 11% 27% 19% 1	3800
	11th to 20th	Night	46% 7% 15% 24% 8%	3779
	21st to end	Night	49% 8% 13% 22% 7%	4120
November	1st to 10th	Night	50% 7% 13% 21% 9%	2559
	11th to 20th	Night	55% 8% 12% 15% 7% 2	2660
	21st to end	Night	62% 8% 14% 12% 4	2660
December	1st to 10th	Night	68% 8% 9% 10% 5%	2660
	11th to 20th	Night	66% 6% 11% 12% 5%	3288
	21st to end	Night	77% 4 7% 9% 3	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	22% 23% 34% 13% 7% 1	180
	11th to 20th	Day	24% 21% 36% 13% 5% 1	209
	21st to end	Day	25% 17% 37% 15% 6%	297
February	1st to 10th	Day	31% 23% 30% 11% 4	270
	11th to 20th	Day	23% 27% 39% 10% 1	270
	21st to end	Day	38% 18% 32% 12%	266
March	1st to 10th	Day	23% 18% 38% 18% 3	460
	11th to 20th	Day	26% 18% 35% 16% 4 1	460
	21st to end	Day	31% 17% 32% 14% 5% 1	506
April	1st to 10th	Day	25% 21% 31% 15% 6% 1	460
	11th to 20th	Day	33% 16% 25% 13% 8% 4	452
	21st to end	Day	29% 15% 34% 13% 8% 2	460
May	1st to 10th	Day	25% 13% 30% 19% 8% 5%	463
	11th to 20th	Day	19% 13% 34% 18% 11% 4	487
	21st to end	Day	16% 12% 34% 21% 11% 6%	529
June	1st to 10th	Day	21% 10% 34% 24% 9% 1	490
	11th to 20th	Day	17% 12% 27% 27% 12% 5%	490
	21st to end	Day	20% 12% 31% 24% 10% 3	490
July	1st to 10th	Day	11% 8% 29% 31% 16% 6%	485
	11th to 20th	Day	14% 9% 27% 28% 15% 6%	484
	21st to end	Day	8% 11% 33% 31% 12% 5%	532
August	1st to 10th	Day	16% 6% 27% 26% 17% 7%	486
	11th to 20th	Day	12% 9% 23% 28% 19% 8%	479
	21st to end	Day	12% 9% 32% 25% 16% 7%	539
September	1st to 10th	Day	14% 11% 29% 24% 16% 6%	490
	11th to 20th	Day	12% 8% 26% 21% 21% 12%	490
	21st to end	Day	19% 13% 28% 23% 13% 5%	490
October	1st to 10th	Day	23% 14% 29% 15% 14% 5%	490
	11th to 20th	Day	25% 19% 32% 16% 6% 2	490
	21st to end	Day	32% 20% 30% 13% 5%	539
November	1st to 10th	Day	28% 18% 31% 18% 6%	257
	11th to 20th	Day	28% 21% 34% 12% 3 2	180
	21st to end	Day	31% 16% 44% 8% 2	180
December	1st to 10th	Day	28% 20% 34% 13% 5%	180
	11th to 20th	Day	29% 26% 27% 13% 3 1	180
	21st to end	Day	32% 20% 35% 11% 2	198
January	1st to 10th	Night	25% 22% 29% 16% 6% 1	760
	11th to 20th	Night	27% 18% 31% 18% 5% 1	760
	21st to end	Night	19% 17% 34% 24% 5% 1	836
February	1st to 10th	Night	22% 22% 36% 18% 2	760
	11th to 20th	Night	23% 19% 37% 17% 4	743
	21st to end	Night	24% 21% 33% 18% 3	628
March	1st to 10th	Night	23% 19% 34% 20% 3	760
	11th to 20th	Night	22% 22% 33% 18% 5% 1	760
	21st to end	Night	20% 14% 36% 23% 7%	836
April	1st to 10th	Night	25% 18% 32% 19% 5%	760
	11th to 20th	Night	24% 15% 32% 20% 9% 1	721
	21st to end	Night	21% 13% 33% 24% 9% 1	570
May	1st to 10th	Night	20% 8% 29% 29% 12% 2	510
	11th to 20th	Night	16% 10% 33% 32% 8%	374
	21st to end	Night	12% 8% 33% 33% 13%	411
June	1st to 10th	Night	16% 9% 31% 34% 9% 1	380
	11th to 20th	Night	13% 9% 27% 37% 13% 1	380
	21st to end	Night	13% 9% 27% 36% 14% 1	380
July	1st to 10th	Night	7% 7% 24% 41% 19% 1	370
	11th to 20th	Night	11% 7% 27% 33% 21% 1	368
	21st to end	Night	10% 5% 27% 39% 18% 1	498
August	1st to 10th	Night	12% 3 23% 34% 26% 2	567
	11th to 20th	Night	9% 6% 21% 34% 26% 4	564
	21st to end	Night	12% 5% 29% 30% 22% 2	727
September	1st to 10th	Night	12% 7% 30% 28% 19% 4	760
	11th to 20th	Night	13% 6% 25% 29% 23% 5%	760
	21st to end	Night	20% 10% 21% 31% 15% 4	760
October	1st to 10th	Night	19% 12% 28% 24% 14% 2	760
	11th to 20th	Night	25% 16% 31% 18% 8% 1	760
	21st to end	Night	29% 19% 29% 19% 5%	836
November	1st to 10th	Night	24% 15% 29% 22% 9% 1	755
	11th to 20th	Night	23% 20% 33% 18% 5% 1	760
	21st to end	Night	28% 19% 29% 20% 5%	760
December	1st to 10th	Night	29% 24% 29% 14% 4	760
	11th to 20th	Night	25% 22% 33% 17% 3 1	760
	21st to end	Night	32% 20% 29% 17% 2	836

Page generated at 2024-11-01 22:47:51. Version ac07

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