Ear Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ear Falls clear sky chart from 2005-11-06 to 2024-09-29.

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% 11% 4 9% 6% 5% 5% 4 5% 7% 30%	101580
	Night	12% 12% 5% 11% 6% 6% 5% 4 5% 6% 28%	96812
Transparency	Day	53% 5% 12% 22% 7% 1	101317
	Night	57% 5% 12% 19% 7% 1	96693
Seeing	Day	20% 12% 32% 24% 10% 2	16185
	Night	20% 9% 30% 29% 12% 1	26039

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	6% 14% 10% 17% 9% 10% 8% 4 4 5% 14%	2218
	11th to 20th	Day	5% 11% 5% 14% 12% 9% 8% 6% 8% 7% 14%	2220
	21st to end	Day	8% 19% 8% 21% 7% 5% 5% 6% 5% 4 11%	2568
February	1st to 10th	Day	7% 14% 5% 11% 8% 7% 9% 7% 6% 6% 21%	1710
	11th to 20th	Day	8% 12% 4 9% 7% 9% 7% 6% 5% 8% 25%	1664
	21st to end	Day	5% 13% 6% 15% 8% 7% 5% 5% 6% 6% 24%	1413
March	1st to 10th	Day	8% 11% 3 14% 6% 4 4 4 4 6% 34%	3246
	11th to 20th	Day	8% 11% 6% 15% 11% 5% 6% 4 4 5% 25%	3480
	21st to end	Day	11% 16% 6% 11% 5% 5% 4 3 5% 5% 30%	3904
April	1st to 10th	Day	11% 14% 4 9% 5% 5% 4 3 5% 6% 35%	2280
	11th to 20th	Day	14% 11% 4 10% 5% 4 4 3 6% 6% 33%	2395
	21st to end	Day	12% 10% 4 8% 6% 5% 5% 4 6% 7% 35%	2550
May	1st to 10th	Day	15% 9% 3 7% 4 5% 5% 4 6% 9% 33%	4428
	11th to 20th	Day	17% 11% 3 8% 4 4 4 3 5% 7% 33%	4399
	21st to end	Day	23% 13% 3 7% 4 4 4 3 4 5% 32%	5132
June	1st to 10th	Day	18% 8% 2 6% 6% 5% 6% 5% 7% 7% 30%	2850
	11th to 20th	Day	18% 9% 3 6% 5% 4 5% 4 6% 7% 31%	2850
	21st to end	Day	16% 7% 2 7% 6% 6% 5% 6% 7% 8% 31%	2850
July	1st to 10th	Day	14% 7% 2 7% 5% 5% 6% 4 6% 8% 38%	4750
	11th to 20th	Day	12% 5% 2 6% 4 4 5% 5% 7% 8% 43%	4750
	21st to end	Day	11% 5% 2 6% 4 6% 5% 5% 6% 8% 41%	5070
August	1st to 10th	Day	17% 6% 2 6% 4 4 4 4 6% 8% 38%	4423
	11th to 20th	Day	10% 4 2 6% 3 4 5% 5% 7% 9% 46%	4071
	21st to end	Day	17% 8% 2 7% 4 4 5% 4 6% 10% 34%	4484
September	1st to 10th	Day	16% 7% 2 7% 5% 5% 5% 4 6% 6% 37%	2280
	11th to 20th	Day	22% 10% 3 7% 5% 5% 4 4 5% 6% 29%	2266
	21st to end	Day	21% 12% 3 6% 5% 3 4 4 4 6% 33%	1971
October	1st to 10th	Day	22% 18% 4 8% 4 5% 4 3 4 5% 24%	1800
	11th to 20th	Day	19% 19% 5% 9% 5% 4 4 3 4 5% 21%	1800
	21st to end	Day	21% 22% 7% 11% 6% 4 3 3 3 5% 16%	1746
November	1st to 10th	Day	16% 21% 6% 13% 6% 5% 4 3 3 5% 18%	1487
	11th to 20th	Day	13% 21% 8% 15% 9% 6% 5% 3 2 4 13%	1520
	21st to end	Day	16% 18% 6% 19% 9% 5% 4 4 4 4 12%	1520
December	1st to 10th	Day	8% 18% 6% 15% 12% 10% 7% 4 4 4 13%	1364
	11th to 20th	Day	8% 17% 8% 16% 7% 5% 6% 5% 5% 4 19%	1679
	21st to end	Day	14% 14% 8% 12% 7% 6% 5% 5% 6% 8% 16%	2442
January	1st to 10th	Night	5% 16% 7% 16% 9% 10% 6% 5% 5% 5% 14%	4737
	11th to 20th	Night	6% 10% 5% 16% 13% 11% 9% 6% 6% 5% 12%	4750
	21st to end	Night	8% 21% 9% 17% 6% 6% 6% 5% 5% 5% 12%	5094
February	1st to 10th	Night	7% 13% 6% 11% 7% 7% 10% 7% 6% 6% 20%	2470
	11th to 20th	Night	8% 13% 4 9% 6% 7% 7% 7% 6% 6% 28%	2403
	21st to end	Night	4 12% 7% 11% 8% 7% 6% 5% 6% 7% 27%	2041
March	1st to 10th	Night	10% 13% 5% 10% 7% 5% 5% 3 5% 5% 30%	3621
	11th to 20th	Night	8% 15% 6% 11% 8% 5% 6% 3 4 6% 29%	3479
	21st to end	Night	12% 17% 4 8% 4 5% 4 3 5% 5% 34%	3727
April	1st to 10th	Night	13% 11% 3 8% 5% 4 4 3 5% 5% 40%	1900
	11th to 20th	Night	13% 10% 4 7% 6% 5% 5% 3 5% 5% 36%	1731
	21st to end	Night	12% 12% 3 8% 6% 4 4 3 4 5% 39%	1629
May	1st to 10th	Night	15% 9% 3 7% 5% 5% 5% 4 5% 6% 36%	2523
	11th to 20th	Night	19% 8% 3 7% 4 4 5% 4 5% 7% 35%	2506
	21st to end	Night	28% 9% 2 5% 4 3 4 3 5% 5% 33%	2453
June	1st to 10th	Night	19% 8% 3 6% 4 5% 4 3 7% 9% 33%	1330
	11th to 20th	Night	15% 8% 2 7% 4 4 4 4 6% 8% 39%	1330
	21st to end	Night	13% 5% 2 5% 4 4 4 4 6% 8% 44%	1330
July	1st to 10th	Night	13% 5% 2 6% 4 3 4 4 7% 7% 46%	2220
	11th to 20th	Night	10% 4 1 6% 4 4 4 3 6% 9% 49%	2220
	21st to end	Night	11% 5% 2 5% 4 3 3 4 5% 8% 49%	2494
August	1st to 10th	Night	15% 6% 2 7% 4 5% 4 3 6% 7% 40%	2517
	11th to 20th	Night	10% 5% 2 5% 3 4 4 4 6% 9% 48%	2765
	21st to end	Night	16% 7% 2 7% 4 4 4 4 5% 8% 39%	3181
September	1st to 10th	Night	15% 7% 2 7% 3 4 3 3 4 7% 45%	1900
	11th to 20th	Night	22% 8% 2 6% 4 3 4 3 4 6% 37%	1912
	21st to end	Night	19% 9% 2 6% 4 4 4 3 5% 7% 37%	2157
October	1st to 10th	Night	18% 14% 4 7% 5% 4 5% 4 5% 6% 30%	2160
	11th to 20th	Night	21% 16% 3 8% 4 4 4 3 4 6% 27%	2160
	21st to end	Night	20% 18% 5% 11% 5% 4 4 3 5% 5% 19%	2606
November	1st to 10th	Night	16% 19% 6% 12% 6% 4 4 3 4 5% 21%	2591
	11th to 20th	Night	16% 17% 6% 16% 9% 7% 5% 3 4 3 16%	2660
	21st to end	Night	15% 19% 7% 16% 10% 6% 5% 4 3 4 12%	2660
December	1st to 10th	Night	8% 15% 7% 17% 12% 9% 6% 3 4 5% 13%	2812
	11th to 20th	Night	9% 15% 7% 16% 8% 6% 6% 5% 5% 6% 17%	3518
	21st to end	Night	10% 16% 8% 15% 9% 7% 7% 4 5% 5% 14%	5225

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	73% 4 7% 12% 4	2219
	11th to 20th	Day	66% 3 13% 15% 3	2220
	21st to end	Day	74% 4 7% 10% 5%	2568
February	1st to 10th	Day	61% 5% 10% 14% 10%	1710
	11th to 20th	Day	57% 4 9% 22% 8%	1673
	21st to end	Day	58% 4 8% 20% 9% 1	1413
March	1st to 10th	Day	51% 4 11% 20% 13% 1	3248
	11th to 20th	Day	60% 5% 8% 19% 7% 1	3480
	21st to end	Day	57% 4 7% 21% 10% 1	3904
April	1st to 10th	Day	51% 4 9% 20% 14% 3	2280
	11th to 20th	Day	51% 3 9% 24% 12% 1	2395
	21st to end	Day	48% 4 10% 25% 11% 2	2550
May	1st to 10th	Day	45% 7% 11% 26% 10% 1	4440
	11th to 20th	Day	50% 6% 12% 20% 12% 2	4403
	21st to end	Day	54% 5% 8% 19% 12% 1	5132
June	1st to 10th	Day	50% 7% 11% 21% 11%	2850
	11th to 20th	Day	49% 5% 12% 20% 13% 1	2850
	21st to end	Day	47% 7% 15% 23% 8%	2850
July	1st to 10th	Day	43% 7% 16% 27% 7%	4676
	11th to 20th	Day	37% 7% 19% 32% 6%	4669
	21st to end	Day	39% 6% 17% 32% 5%	4909
August	1st to 10th	Day	43% 5% 14% 29% 9%	4408
	11th to 20th	Day	32% 7% 24% 34% 3	4111
	21st to end	Day	44% 6% 20% 26% 4	4483
September	1st to 10th	Day	45% 6% 16% 27% 6%	2280
	11th to 20th	Day	55% 6% 14% 22% 3	2266
	21st to end	Day	52% 4 16% 22% 5%	1971
October	1st to 10th	Day	63% 5% 12% 17% 3	1800
	11th to 20th	Day	65% 4 11% 17% 3	1800
	21st to end	Day	72% 4 12% 11% 1	1746
November	1st to 10th	Day	70% 4 11% 10% 5% 1	1487
	11th to 20th	Day	77% 3 8% 9% 3	1520
	21st to end	Day	76% 3 10% 7% 2	1520
December	1st to 10th	Day	74% 3 9% 11% 3	1364
	11th to 20th	Day	65% 6% 8% 17% 4	1680
	21st to end	Day	65% 4 9% 17% 6%	2442
January	1st to 10th	Night	71% 4 9% 13% 3	4737
	11th to 20th	Night	72% 4 11% 10% 3	4750
	21st to end	Night	73% 5% 9% 9% 4	5094
February	1st to 10th	Night	60% 6% 10% 16% 8%	2470
	11th to 20th	Night	54% 5% 10% 23% 8%	2404
	21st to end	Night	55% 4 9% 21% 10% 1	2041
March	1st to 10th	Night	55% 5% 7% 17% 15% 1	3632
	11th to 20th	Night	57% 4 11% 20% 7% 2	3480
	21st to end	Night	53% 4 7% 19% 15% 2	3727
April	1st to 10th	Night	45% 3 8% 23% 18% 3	1900
	11th to 20th	Night	50% 3 7% 20% 18% 2	1731
	21st to end	Night	48% 4 7% 23% 15% 2	1629
May	1st to 10th	Night	47% 7% 8% 27% 11%	2530
	11th to 20th	Night	48% 6% 13% 22% 10% 1	2507
	21st to end	Night	53% 5% 9% 20% 12% 2	2454
June	1st to 10th	Night	47% 6% 13% 20% 12% 1	1330
	11th to 20th	Night	42% 5% 12% 24% 15% 1	1330
	21st to end	Night	37% 7% 17% 28% 10% 1	1330
July	1st to 10th	Night	35% 7% 19% 27% 11% 1	2185
	11th to 20th	Night	31% 5% 21% 36% 6% 1	2178
	21st to end	Night	33% 5% 18% 36% 7%	2415
August	1st to 10th	Night	43% 5% 13% 30% 9% 1	2508
	11th to 20th	Night	32% 6% 22% 36% 5%	2791
	21st to end	Night	43% 5% 21% 25% 4	3181
September	1st to 10th	Night	39% 5% 16% 30% 9%	1900
	11th to 20th	Night	48% 6% 17% 25% 5%	1912
	21st to end	Night	47% 5% 18% 24% 6%	2157
October	1st to 10th	Night	56% 6% 12% 22% 5%	2160
	11th to 20th	Night	59% 5% 14% 19% 3	2160
	21st to end	Night	67% 5% 12% 14% 3	2606
November	1st to 10th	Night	67% 3 12% 15% 3	2591
	11th to 20th	Night	73% 4 8% 11% 3	2660
	21st to end	Night	78% 3 10% 8% 2	2660
December	1st to 10th	Night	75% 3 9% 9% 3	2812
	11th to 20th	Night	67% 5% 9% 13% 5%	3516
	21st to end	Night	71% 4 6% 14% 4	5225

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% 9% 41% 23% 9% 1	270
	11th to 20th	Day	12% 8% 37% 31% 11% 1	270
	21st to end	Day	14% 8% 38% 28% 11% 1	297
February	1st to 10th	Day	20% 10% 44% 17% 7% 2	270
	11th to 20th	Day	14% 17% 33% 23% 12% 1	270
	21st to end	Day	13% 17% 43% 17% 8% 2	225
March	1st to 10th	Day	16% 8% 42% 24% 9% 1	270
	11th to 20th	Day	14% 17% 39% 23% 6%	270
	21st to end	Day	19% 13% 37% 21% 9% 1	349
April	1st to 10th	Day	18% 14% 32% 25% 10% 2	460
	11th to 20th	Day	22% 12% 31% 25% 8% 1	593
	21st to end	Day	17% 13% 36% 25% 9% 1	650
May	1st to 10th	Day	21% 15% 34% 23% 6% 1	653
	11th to 20th	Day	23% 14% 30% 22% 8% 3	675
	21st to end	Day	25% 10% 31% 24% 8% 2	734
June	1st to 10th	Day	22% 14% 30% 23% 9% 3	680
	11th to 20th	Day	22% 15% 33% 20% 8% 2	680
	21st to end	Day	18% 10% 28% 27% 13% 3	680
July	1st to 10th	Day	13% 12% 32% 25% 14% 4	671
	11th to 20th	Day	17% 11% 28% 25% 15% 4	668
	21st to end	Day	12% 7% 29% 31% 16% 6%	739
August	1st to 10th	Day	16% 11% 28% 29% 12% 4	676
	11th to 20th	Day	15% 9% 26% 30% 17% 4	665
	21st to end	Day	22% 8% 30% 26% 12% 2	726
September	1st to 10th	Day	21% 11% 30% 27% 10% 1	490
	11th to 20th	Day	28% 11% 32% 23% 6%	476
	21st to end	Day	28% 14% 34% 19% 4	294
October	1st to 10th	Day	34% 10% 25% 21% 10%	270
	11th to 20th	Day	25% 15% 34% 19% 7%	270
	21st to end	Day	36% 15% 30% 16% 3	297
November	1st to 10th	Day	26% 16% 34% 18% 6% 1	270
	11th to 20th	Day	25% 16% 37% 16% 6% 1	270
	21st to end	Day	25% 21% 39% 11% 4	270
December	1st to 10th	Day	17% 12% 36% 24% 8% 2	270
	11th to 20th	Day	21% 11% 39% 24% 4	270
	21st to end	Day	17% 9% 34% 25% 12% 2	297
January	1st to 10th	Night	15% 11% 35% 27% 10% 2	950
	11th to 20th	Night	18% 7% 34% 31% 9% 1	950
	21st to end	Night	17% 8% 34% 31% 9% 1	1045
February	1st to 10th	Night	13% 9% 34% 32% 10% 1	950
	11th to 20th	Night	15% 10% 31% 28% 15% 1	929
	21st to end	Night	11% 11% 33% 30% 13% 3	785
March	1st to 10th	Night	16% 12% 31% 30% 11% 1	711
	11th to 20th	Night	17% 13% 34% 24% 10% 1	570
	21st to end	Night	20% 8% 29% 27% 12% 4	627
April	1st to 10th	Night	18% 10% 26% 36% 10% 1	570
	11th to 20th	Night	18% 8% 31% 28% 13% 1	563
	21st to end	Night	19% 9% 32% 29% 10% 1	570
May	1st to 10th	Night	22% 9% 33% 27% 9% 1	570
	11th to 20th	Night	26% 6% 25% 29% 12% 1	561
	21st to end	Night	27% 8% 26% 28% 11%	617
June	1st to 10th	Night	25% 6% 24% 30% 14% 1	570
	11th to 20th	Night	19% 7% 30% 31% 12% 1	570
	21st to end	Night	16% 6% 22% 37% 18% 1	570
July	1st to 10th	Night	10% 7% 29% 36% 16% 1	555
	11th to 20th	Night	14% 5% 28% 33% 19% 1	552
	21st to end	Night	10% 5% 24% 35% 22% 4	624
August	1st to 10th	Night	15% 4 26% 34% 19% 1	567
	11th to 20th	Night	15% 5% 22% 34% 21% 3	564
	21st to end	Night	20% 6% 24% 32% 17% 1	627
September	1st to 10th	Night	20% 6% 27% 30% 15% 2	570
	11th to 20th	Night	27% 7% 24% 29% 12% 2	570
	21st to end	Night	25% 8% 27% 27% 12% 1	645
October	1st to 10th	Night	28% 8% 29% 27% 9%	720
	11th to 20th	Night	32% 8% 26% 23% 10% 1	720
	21st to end	Night	29% 11% 28% 24% 7% 1	877
November	1st to 10th	Night	24% 12% 30% 22% 9% 2	925
	11th to 20th	Night	26% 9% 33% 23% 8% 1	950
	21st to end	Night	27% 15% 31% 21% 5% 1	950
December	1st to 10th	Night	15% 10% 37% 26% 10% 1	950
	11th to 20th	Night	18% 12% 34% 26% 8% 1	950
	21st to end	Night	20% 10% 30% 28% 10% 2	1045

Page generated at 2024-09-26 08:52:23. Version ac07

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