Spike Day's definition taken from Jack D Schwager's Book: A Complete Guide to the Market: , Trading Systems, , Options, Spreads, and Trading Principles
A spike is:
- A wide difference between the spike high and the highs of the preceding and succeeding days.
- A close near the low of the day's range.
- A substantial price advance preceding the spike's formation.
The more extreme each of these conditions, the greater the likelihood that a spike high will prove to be an important relative high or even a major top.
(inverse is true for lows, basically)